aboutsummaryrefslogtreecommitdiff
path: root/Documentation/kernel-parameters.txt
blob: 1e183bd33d71f3c578a4e2f52966af2b3eab41c4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
                          Kernel Parameters
                          ~~~~~~~~~~~~~~~~~

The following is a consolidated list of the kernel parameters as implemented
(mostly) by the __setup() macro and sorted into English Dictionary order
(defined as ignoring all punctuation and sorting digits before letters in a
case insensitive manner), and with descriptions where known.

Module parameters for loadable modules are specified only as the
parameter name with optional '=' and value as appropriate, such as:

	modprobe usbcore blinkenlights=1

Module parameters for modules that are built into the kernel image
are specified on the kernel command line with the module name plus
'.' plus parameter name, with '=' and value if appropriate, such as:

	usbcore.blinkenlights=1

This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
module. Loadable modules, after being loaded into the running kernel, also
reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
parameters may be changed at runtime by the command
"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".

The parameters listed below are only valid if certain kernel build options were
enabled and if respective hardware is present. The text in square brackets at
the beginning of each description states the restrictions within which a
parameter is applicable:

	ACPI	ACPI support is enabled.
	ALSA	ALSA sound support is enabled.
	APIC	APIC support is enabled.
	APM	Advanced Power Management support is enabled.
	AX25	Appropriate AX.25 support is enabled.
	CD	Appropriate CD support is enabled.
	DRM	Direct Rendering Management support is enabled.
	EDD	BIOS Enhanced Disk Drive Services (EDD) is enabled
	EFI	EFI Partitioning (GPT) is enabled
	EIDE	EIDE/ATAPI support is enabled.
	FB	The frame buffer device is enabled.
	HW	Appropriate hardware is enabled.
	IA-32	IA-32 aka i386 architecture is enabled.
	IA-64	IA-64 architecture is enabled.
	IOSCHED	More than one I/O scheduler is enabled.
	IP_PNP	IP DHCP, BOOTP, or RARP is enabled.
	ISAPNP	ISA PnP code is enabled.
	ISDN	Appropriate ISDN support is enabled.
	JOY	Appropriate joystick support is enabled.
	LP	Printer support is enabled.
	LOOP	Loopback device support is enabled.
	M68k	M68k architecture is enabled.
			These options have more detailed description inside of
			Documentation/m68k/kernel-options.txt.
	MCA	MCA bus support is enabled.
	MDA	MDA console support is enabled.
	MOUSE	Appropriate mouse support is enabled.
	MSI	Message Signaled Interrupts (PCI).
	MTD	MTD support is enabled.
	NET	Appropriate network support is enabled.
	NUMA	NUMA support is enabled.
	GENERIC_TIME The generic timeofday code is enabled.
	NFS	Appropriate NFS support is enabled.
	OSS	OSS sound support is enabled.
	PARIDE	The ParIDE subsystem is enabled.
	PARISC	The PA-RISC architecture is enabled.
	PCI	PCI bus support is enabled.
	PCMCIA	The PCMCIA subsystem is enabled.
	PNP	Plug & Play support is enabled.
	PPC	PowerPC architecture is enabled.
	PPT	Parallel port support is enabled.
	PS2	Appropriate PS/2 support is enabled.
	RAM	RAM disk support is enabled.
	S390	S390 architecture is enabled.
	SCSI	Appropriate SCSI support is enabled.
			A lot of drivers has their options described inside of
			Documentation/scsi/.
	SELINUX SELinux support is enabled.
	SERIAL	Serial support is enabled.
	SMP	The kernel is an SMP kernel.
	SPARC	Sparc architecture is enabled.
	SWSUSP	Software suspend is enabled.
	TS	Appropriate touchscreen support is enabled.
	USB	USB support is enabled.
	USBHID	USB Human Interface Device support is enabled.
	V4L	Video For Linux support is enabled.
	VGA	The VGA console has been enabled.
	VT	Virtual terminal support is enabled.
	WDT	Watchdog support is enabled.
	XT	IBM PC/XT MFM hard disk support is enabled.
	X86-64	X86-64 architecture is enabled.
			More X86-64 boot options can be found in
			Documentation/x86_64/boot-options.txt .

In addition, the following text indicates that the option:

	BUGS=	Relates to possible processor bugs on the said processor.
	KNL	Is a kernel start-up parameter.
	BOOT	Is a boot loader parameter.

Parameters denoted with BOOT are actually interpreted by the boot
loader, and have no meaning to the kernel directly.
Do not modify the syntax of boot loader parameters without extreme
need or coordination with <Documentation/i386/boot.txt>.

Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
be entered as an environment variable, whereas its absence indicates that
it will appear as a kernel argument readable via /proc/cmdline by programs
running once the system is up.

The number of kernel parameters is not limited, but the length of the
complete command line (parameters including spaces etc.) is limited to
a fixed number of characters. This limit depends on the architecture
and is between 256 and 4096 characters. It is defined in the file
./include/asm/setup.h as COMMAND_LINE_SIZE.


	53c7xx=		[HW,SCSI] Amiga SCSI controllers
			See header of drivers/scsi/53c7xx.c.
			See also Documentation/scsi/ncr53c7xx.txt.

	acpi=		[HW,ACPI] Advanced Configuration and Power Interface
			Format: { force | off | ht | strict | noirq }
			force -- enable ACPI if default was off
			off -- disable ACPI if default was on
			noirq -- do not use ACPI for IRQ routing
			ht -- run only enough ACPI to enable Hyper Threading
			strict -- Be less tolerant of platforms that are not
				strictly ACPI specification compliant.

			See also Documentation/pm.txt, pci=noacpi

	acpi_sleep=	[HW,ACPI] Sleep options
			Format: { s3_bios, s3_mode }
			See Documentation/power/video.txt

	acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
			Format: { level | edge | high | low }

	acpi_irq_balance [HW,ACPI]
			ACPI will balance active IRQs
			default in APIC mode

	acpi_irq_nobalance [HW,ACPI]
			ACPI will not move active IRQs (default)
			default in PIC mode

	acpi_irq_pci=	[HW,ACPI] If irq_balance, clear listed IRQs for
			use by PCI
			Format: <irq>,<irq>...

	acpi_irq_isa=	[HW,ACPI] If irq_balance, mark listed IRQs used by ISA
			Format: <irq>,<irq>...

	acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
			Format: To spoof as Windows 98: ="Microsoft Windows"

	acpi_osi=	[HW,ACPI] empty param disables _OSI

	acpi_serialize	[HW,ACPI] force serialization of AML methods

	acpi_skip_timer_override [HW,ACPI]
			Recognize and ignore IRQ0/pin2 Interrupt Override.
			For broken nForce2 BIOS resulting in XT-PIC timer.
	acpi_use_timer_override [HW,ACPI}
			Use timer override. For some broken Nvidia NF5 boards
			that require a timer override, but don't have
			HPET

	acpi_dbg_layer=	[HW,ACPI]
			Format: <int>
			Each bit of the <int> indicates an ACPI debug layer,
			1: enable, 0: disable. It is useful for boot time
			debugging. After system has booted up, it can be set
			via /proc/acpi/debug_layer.

	acpi_dbg_level=	[HW,ACPI]
			Format: <int>
			Each bit of the <int> indicates an ACPI debug level,
			1: enable, 0: disable. It is useful for boot time
			debugging. After system has booted up, it can be set
			via /proc/acpi/debug_level.

	acpi_fake_ecdt	[HW,ACPI] Workaround failure due to BIOS lacking ECDT

	acpi_generic_hotkey [HW,ACPI]
			Allow consolidated generic hotkey driver to
			override platform specific driver.
			See also Documentation/acpi-hotkey.txt.

	acpi_pm_good	[IA-32,X86-64]
			Override the pmtimer bug detection: force the kernel
			to assume that this machine's pmtimer latches its value
			and always returns good values.

	enable_timer_pin_1 [i386,x86-64]
			Enable PIN 1 of APIC timer
			Can be useful to work around chipset bugs
			(in particular on some ATI chipsets).
			The kernel tries to set a reasonable default.

	disable_timer_pin_1 [i386,x86-64]
			Disable PIN 1 of APIC timer
			Can be useful to work around chipset bugs.

	ad1816=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>
			See also Documentation/sound/oss/AD1816.

	ad1848=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<type>

	adlib=		[HW,OSS]
			Format: <io>

	advansys=	[HW,SCSI]
			See header of drivers/scsi/advansys.c.

	advwdt=		[HW,WDT] Advantech WDT
			Format: <iostart>,<iostop>

	aedsp16=	[HW,OSS] Audio Excel DSP 16
			Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
			See also header of sound/oss/aedsp16.c.

	aha152x=	[HW,SCSI]
			See Documentation/scsi/aha152x.txt.

	aha1542=	[HW,SCSI]
			Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]

	aic7xxx=	[HW,SCSI]
			See Documentation/scsi/aic7xxx.txt.

	aic79xx=	[HW,SCSI]
			See Documentation/scsi/aic79xx.txt.

	amijoy.map=	[HW,JOY] Amiga joystick support
			Map of devices attached to JOY0DAT and JOY1DAT
			Format: <a>,<b>
			See also Documentation/kernel/input/joystick.txt

	analog.map=	[HW,JOY] Analog joystick and gamepad support
			Specifies type or capabilities of an analog joystick
			connected to one of 16 gameports
			Format: <type1>,<type2>,..<type16>

	apc=		[HW,SPARC]
			Power management functions (SPARCstation-4/5 + deriv.)
			Format: noidle
			Disable APC CPU standby support. SPARCstation-Fox does
			not play well with APC CPU idle - disable it if you have
			APC and your system crashes randomly.

	apic=		[APIC,i386] Change the output verbosity whilst booting
			Format: { quiet (default) | verbose | debug }
			Change the amount of debugging information output
			when initialising the APIC and IO-APIC components.

	apm=		[APM] Advanced Power Management
			See header of arch/i386/kernel/apm.c.

	applicom=	[HW]
			Format: <mem>,<irq>

	arcrimi=	[HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
			Format: <io>,<irq>,<nodeID>

	ataflop=	[HW,M68k]

	atarimouse=	[HW,MOUSE] Atari Mouse

	atascsi=	[HW,SCSI] Atari SCSI

	atkbd.extra=	[HW] Enable extra LEDs and keys on IBM RapidAccess,
			EzKey and similar keyboards

	atkbd.reset=	[HW] Reset keyboard during initialization

	atkbd.set=	[HW] Select keyboard code set
			Format: <int> (2 = AT (default), 3 = PS/2)

	atkbd.scroll=	[HW] Enable scroll wheel on MS Office and similar
			keyboards

	atkbd.softraw=	[HW] Choose between synthetic and real raw mode
			Format: <bool> (0 = real, 1 = synthetic (default))

	atkbd.softrepeat= [HW]
			Use software keyboard repeat

	autotest	[IA64]

	aztcd=		[HW,CD] Aztech CD268 CDROM driver
			Format: <io>,0x79 (?)

	baycom_epp=	[HW,AX25]
			Format: <io>,<mode>

	baycom_par=	[HW,AX25] BayCom Parallel Port AX.25 Modem
			Format: <io>,<mode>
			See header of drivers/net/hamradio/baycom_par.c.

	baycom_ser_fdx=	[HW,AX25]
			BayCom Serial Port AX.25 Modem (Full Duplex Mode)
			Format: <io>,<irq>,<mode>[,<baud>]
			See header of drivers/net/hamradio/baycom_ser_fdx.c.

	baycom_ser_hdx=	[HW,AX25]
			BayCom Serial Port AX.25 Modem (Half Duplex Mode)
			Format: <io>,<irq>,<mode>
			See header of drivers/net/hamradio/baycom_ser_hdx.c.

	blkmtd_device=	[HW,MTD]
	blkmtd_erasesz=
	blkmtd_ro=
	blkmtd_bs=
	blkmtd_count=

	bttv.card=	[HW,V4L] bttv (bt848 + bt878 based grabber cards)
	bttv.radio=	Most important insmod options are available as
			kernel args too.
	bttv.pll=	See Documentation/video4linux/bttv/Insmod-options
	bttv.tuner=	and Documentation/video4linux/bttv/CARDLIST

	BusLogic=	[HW,SCSI]
			See drivers/scsi/BusLogic.c, comment before function
			BusLogic_ParseDriverOptions().

	c101=		[NET] Moxa C101 synchronous serial card

	cachesize=	[BUGS=IA-32] Override level 2 CPU cache size detection.
			Sometimes CPU hardware bugs make them report the cache
			size incorrectly. The kernel will attempt work arounds
			to fix known problems, but for some CPUs it is not
			possible to determine what the correct size should be.
			This option provides an override for these situations.

	cdu31a=		[HW,CD]
			Format: <io>,<irq>[,PAS]
			See header of drivers/cdrom/cdu31a.c.

	chandev=	[HW,NET] Generic channel device initialisation

	checkreqprot	[SELINUX] Set initial checkreqprot flag value.
			Format: { "0" | "1" }
			See security/selinux/Kconfig help text.
			0 -- check protection applied by kernel (includes
				any implied execute protection).
			1 -- check protection requested by application.
			Default value is set via a kernel config option.
			Value can be changed at runtime via
				/selinux/checkreqprot.

	clock=		[BUGS=IA-32, HW] gettimeofday clocksource override.
			[Deprecated]
			Forces specified clocksource (if available) to be used
			when calculating gettimeofday(). If specified
			clocksource is not available, it defaults to PIT.
			Format: { pit | tsc | cyclone | pmtmr }

	disable_8254_timer
	enable_8254_timer
			[IA32/X86_64] Disable/Enable interrupt 0 timer routing
			over the 8254 in addition to over the IO-APIC. The
			kernel tries to set a sensible default.

	hpet=		[IA-32,HPET] option to disable HPET and use PIT.
			Format: disable

	cm206=		[HW,CD]
			Format: { auto | [<io>,][<irq>] }

	com20020=	[HW,NET] ARCnet - COM20020 chipset
			Format:
			<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]

	com90io=	[HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
			Format: <io>[,<irq>]

	com90xx=	[HW,NET]
			ARCnet - COM90xx chipset (memory-mapped buffers)
			Format: <io>[,<irq>[,<memstart>]]

	condev=		[HW,S390] console device
	conmode=

	console=	[KNL] Output console device and options.

		tty<n>	Use the virtual console device <n>.

		ttyS<n>[,options]
		ttyUSB0[,options]
			Use the specified serial port.  The options are of
			the form "bbbbpnf", where "bbbb" is the baud rate,
			"p" is parity ("n", "o", or "e"), "n" is number of
			bits, and "f" is flow control ("r" for RTS or
			omit it).  Default is "9600n8".

			See Documentation/serial-console.txt for more
			information.  See
			Documentation/networking/netconsole.txt for an
			alternative.

		uart,io,<addr>[,options]
		uart,mmio,<addr>[,options]
			Start an early, polled-mode console on the 8250/16550
			UART at the specified I/O port or MMIO address,
			switching to the matching ttyS device later.  The
			options are the same as for ttyS, above.

	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver
			Format:
			<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

	cpia_pp=	[HW,PPT]
			Format: { parport<nr> | auto | none }

	crashkernel=nn[KMG]@ss[KMG]
			[KNL] Reserve a chunk of physical memory to
			hold a kernel to switch to with kexec on panic.

	cs4232=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>

	cs89x0_dma=	[HW,NET]
			Format: <dma>

	cs89x0_media=	[HW,NET]
			Format: { rj45 | aui | bnc }

	cyclades=	[HW,SERIAL] Cyclades multi-serial port adapter.

	dasd=		[HW,NET]
			See header of drivers/s390/block/dasd_devmap.c.

	db9.dev[2|3]=	[HW,JOY] Multisystem joystick support via parallel port
			(one device per port)
			Format: <port#>,<type>
			See also Documentation/input/joystick-parport.txt

	debug		[KNL] Enable kernel debugging (events log level).

	debug_locks_verbose=
			[KNL] verbose self-tests
			Format=<0|1>
			Print debugging info while doing the locking API
			self-tests.
			We default to 0 (no extra messages), setting it to
			1 will print _a lot_ more information - normally
			only useful to kernel developers.

	decnet=		[HW,NET]
			Format: <area>[,<node>]
			See also Documentation/networking/decnet.txt.

	dhash_entries=	[KNL]
			Set number of hash buckets for dentry cache.

	digi=		[HW,SERIAL]
			IO parameters + enable/disable command.

	digiepca=	[HW,SERIAL]
			See drivers/char/README.epca and
			Documentation/digiepca.txt.

	dmascc=		[HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
			support available.
			Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]

	dmasound=	[HW,OSS] Sound subsystem buffers

	dscc4.setup=	[NET]

	dtc3181e=	[HW,SCSI]

	earlyprintk=	[IA-32,X86-64]
			earlyprintk=vga
			earlyprintk=serial[,ttySn[,baudrate]]

			Append ",keep" to not disable it when the real console
			takes over.

			Only vga or serial at a time, not both.

			Currently only ttyS0 and ttyS1 are supported.

			Interaction with the standard serial driver is not
			very good.

			The VGA output is eventually overwritten by the real
			console.

	eata=		[HW,SCSI]

	ec_intr=	[HW,ACPI] ACPI Embedded Controller interrupt mode
			Format: <int>
			0: polling mode
			non-0: interrupt mode (default)

	eda=		[HW,PS2]

	edb=		[HW,PS2]

	edd=		[EDD]
			Format: {"of[f]" | "sk[ipmbr]"}
			See comment in arch/i386/boot/edd.S

	eicon=		[HW,ISDN]
			Format: <id>,<membase>,<irq>

	eisa_irq_edge=	[PARISC,HW]
			See header of drivers/parisc/eisa.c.

	elanfreq=	[IA-32]
			See comment before function elanfreq_setup() in
			arch/i386/kernel/cpu/cpufreq/elanfreq.c.

	elevator=	[IOSCHED]
			Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
			See Documentation/block/as-iosched.txt and
			Documentation/block/deadline-iosched.txt for details.

	elfcorehdr=	[IA-32, X86_64]
			Specifies physical address of start of kernel core
			image elf header. Generally kexec loader will
			pass this option to capture kernel.
			See Documentation/kdump/kdump.txt for details.

	enforcing	[SELINUX] Set initial enforcing status.
			Format: {"0" | "1"}
			See security/selinux/Kconfig help text.
			0 -- permissive (log only, no denials).
			1 -- enforcing (deny and log).
			Default value is 0.
			Value can be changed at runtime via /selinux/enforce.

	es1371=		[HW,OSS]
			Format: <spdif>,[<nomix>,[<amplifier>]]
			See also header of sound/oss/es1371.c.

	ether=		[HW,NET] Ethernet cards parameters
			This option is obsoleted by the "netdev=" option, which
			has equivalent usage. See its documentation for details.

	eurwdt=		[HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
			Format: <io>[,<irq>]

	fd_mcs=		[HW,SCSI]
			See header of drivers/scsi/fd_mcs.c.

	fdomain=	[HW,SCSI]
			See header of drivers/scsi/fdomain.c.

	floppy=		[HW]
			See Documentation/floppy.txt.

	gamecon.map[2|3]=
			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
			support via parallel port (up to 5 devices per port)
			Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
			See also Documentation/input/joystick-parport.txt

	gamma=		[HW,DRM]

	gdth=		[HW,SCSI]
			See header of drivers/scsi/gdth.c.

	gpt		[EFI] Forces disk with valid GPT signature but
			invalid Protective MBR to be treated as GPT.

	gscd=		[HW,CD]
			Format: <io>

	gvp11=		[HW,SCSI]

	hashdist=	[KNL,NUMA] Large hashes allocated during boot
			are distributed across NUMA nodes.  Defaults on
			for IA-64, off otherwise.
			Format: 0 | 1 (for off | on)

	hcl=		[IA-64] SGI's Hardware Graph compatibility layer

	hd=		[EIDE] (E)IDE hard drive subsystem geometry
			Format: <cyl>,<head>,<sect>

	hd?=		[HW] (E)IDE subsystem
	hd?lun=		See Documentation/ide.txt.

	highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
			size of <nn>. This works even on boxes that have no
			highmem otherwise. This also works to reduce highmem
			size on bigger boxes.

	hisax=		[HW,ISDN]
			See Documentation/isdn/README.HiSax.

	hugepages=	[HW,IA-32,IA-64] Maximal number of HugeTLB pages.

	noirqbalance	[IA-32,SMP,KNL] Disable kernel irq balancing

	i8042.direct	[HW] Put keyboard port into non-translated mode
	i8042.dumbkbd	[HW] Pretend that controller can only read data from
			     keyboard and cannot control its state
			     (Don't attempt to blink the leds)
	i8042.noaux	[HW] Don't check for auxiliary (== mouse) port
	i8042.nokbd	[HW] Don't check/create keyboard port
	i8042.nomux	[HW] Don't check presence of an active multiplexing
			     controller
	i8042.nopnp	[HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
			     controllers
	i8042.panicblink=
			[HW] Frequency with which keyboard LEDs should blink
			     when kernel panics (default is 0.5 sec)
	i8042.reset	[HW] Reset the controller during init and cleanup
	i8042.unlock	[HW] Unlock (ignore) the keylock

	i810=		[HW,DRM]

	i8k.ignore_dmi	[HW] Continue probing hardware even if DMI data
			indicates that the driver is running on unsupported
			hardware.
	i8k.force	[HW] Activate i8k driver even if SMM BIOS signature
			does not match list of supported models.
	i8k.power_status
			[HW] Report power status in /proc/i8k
			(disabled by default)
	i8k.restricted	[HW] Allow controlling fans only if SYS_ADMIN
			capability is set.

	ibmmcascsi=	[HW,MCA,SCSI] IBM MicroChannel SCSI adapter
			See Documentation/mca.txt.

	icn=		[HW,ISDN]
			Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]

	ide=		[HW] (E)IDE subsystem
			Format: ide=nodma or ide=doubler or ide=reverse
			See Documentation/ide.txt.

	ide?=		[HW] (E)IDE subsystem
			Format: ide?=noprobe or chipset specific parameters.
			See Documentation/ide.txt.

	idebus=		[HW] (E)IDE subsystem - VLB/PCI bus speed
			See Documentation/ide.txt.

	idle=		[HW]
			Format: idle=poll or idle=halt

	ihash_entries=	[KNL]
			Set number of hash buckets for inode cache.

	in2000=		[HW,SCSI]
			See header of drivers/scsi/in2000.c.

	init=		[KNL]
			Format: <full_path>
			Run specified binary instead of /sbin/init as init
			process.

	initcall_debug	[KNL] Trace initcalls as they are executed.  Useful
			for working out where the kernel is dying during
			startup.

	initrd=		[BOOT] Specify the location of the initial ramdisk

	inport.irq=	[HW] Inport (ATI XL and Microsoft) busmouse driver
			Format: <irq>

	combined_mode=	[HW] control which driver uses IDE ports in combined
			mode: legacy IDE driver, libata, or both
			(in the libata case, libata.atapi_enabled=1 may be
			useful as well).  Note that using the ide or libata
			options may affect your device naming (e.g. by
			changing hdc to sdb).
			Format: combined (default), ide, or libata

	inttest=	[IA64]

	io7=		[HW] IO7 for Marvel based alpha systems
			See comment before marvel_specify_io7 in
			arch/alpha/kernel/core_marvel.c.

	ip=		[IP_PNP]
			See Documentation/nfsroot.txt.

	ip2=		[HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
			See comment before ip2_setup() in drivers/char/ip2.c.

	ips=		[HW,SCSI] Adaptec / IBM ServeRAID controller
			See header of drivers/scsi/ips.c.

	ports=		[IP_VS_FTP] IPVS ftp helper module
			Default is 21.
			Up to 8 (IP_VS_APP_MAX_PORTS) ports
			may be specified.
			Format: <port>,<port>....

	irqfixup	[HW]
			When an interrupt is not handled search all handlers
			for it. Intended to get systems with badly broken
			firmware running.

	irqpoll		[HW]
			When an interrupt is not handled search all handlers
			for it. Also check all handlers each timer
			interrupt. Intended to get systems with badly broken
			firmware running.

	isapnp=		[ISAPNP]
			Format: <RDP>,<reset>,<pci_scan>,<verbosity>

	isolcpus=	[KNL,SMP] Isolate CPUs from the general scheduler.
			Format: <cpu number>,...,<cpu number>
			This option can be used to specify one or more CPUs
			to isolate from the general SMP balancing and scheduling
			algorithms. The only way to move a process onto or off
			an "isolated" CPU is via the CPU affinity syscalls.
			<cpu number> begins at 0 and the maximum value is
			"number of CPUs in system - 1".

			This option is the preferred way to isolate CPUs. The
			alternative -- manually setting the CPU mask of all
			tasks in the system -- can cause problems and
			suboptimal load balancer performance.

	isp16=		[HW,CD]
			Format: <io>,<irq>,<dma>,<setup>

	iucv=		[HW,NET]

	js=		[HW,JOY] Analog joystick
			See Documentation/input/joystick.txt.

	keepinitrd	[HW,ARM]

	kstack=N	[IA-32,X86-64] Print N words from the kernel stack
			in oops dumps.

	l2cr=		[PPC]

	lapic		[IA-32,APIC] Enable the local APIC even if BIOS
			disabled it.

	lasi=		[HW,SCSI] PARISC LASI driver for the 53c700 chip
			Format: addr:<io>,irq:<irq>

	llsc*=		[IA64] See function print_params() in
			arch/ia64/sn/kernel/llsc4.c.

	load_ramdisk=	[RAM] List of ramdisks to load from floppy
			See Documentation/ramdisk.txt.

	lockd.nlm_grace_period=P  [NFS] Assign grace period.
			Format: <integer>

	lockd.nlm_tcpport=N	[NFS] Assign TCP port.
			Format: <integer>

	lockd.nlm_timeout=T	[NFS] Assign timeout value.
			Format: <integer>

	lockd.nlm_udpport=M	[NFS] Assign UDP port.
			Format: <integer>

	logibm.irq=	[HW,MOUSE] Logitech Bus Mouse Driver
			Format: <irq>

	loglevel=	All Kernel Messages with a loglevel smaller than the
			console loglevel will be printed to the console. It can
			also be changed with klogd or other programs. The
			loglevels are defined as follows:

			0 (KERN_EMERG)		system is unusable
			1 (KERN_ALERT)		action must be taken immediately
			2 (KERN_CRIT)		critical conditions
			3 (KERN_ERR)		error conditions
			4 (KERN_WARNING)	warning conditions
			5 (KERN_NOTICE)		normal but significant condition
			6 (KERN_INFO)		informational
			7 (KERN_DEBUG)		debug-level messages

	log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
			Format: { n | nk | nM }
			n must be a power of two.  The default size
			is set in the kernel config file.

	lp=0		[LP]	Specify parallel ports to use, e.g,
	lp=port[,port...]	lp=none,parport0 (lp0 not configured, lp1 uses
	lp=reset		first parallel port). 'lp=0' disables the
	lp=auto			printer driver. 'lp=reset' (which can be
				specified in addition to the ports) causes
				attached printers to be reset. Using
				lp=port1,port2,... specifies the parallel ports
				to associate lp devices with, starting with
				lp0. A port specification may be 'none' to skip
				that lp device, or a parport name such as
				'parport0'. Specifying 'lp=auto' instead of a
				port specification list means that device IDs
				from each port should be examined, to see if
				an IEEE 1284-compliant printer is attached; if
				so, the driver will manage that printer.
				See also header of drivers/char/lp.c.

	lpj=n		[KNL]
			Sets loops_per_jiffy to given constant, thus avoiding
			time-consuming boot-time autodetection (up to 250 ms per
			CPU). 0 enables autodetection (default). To determine
			the correct value for your kernel, boot with normal
			autodetection and see what value is printed. Note that
			on SMP systems the preset will be applied to all CPUs,
			which is likely to cause problems if your CPUs need
			significantly divergent settings. An incorrect value
			will cause delays in the kernel to be wrong, leading to
			unpredictable I/O errors and other breakage. Although
			unlikely, in the extreme case this might damage your
			hardware.

	ltpc=		[NET]
			Format: <io>,<irq>,<dma>

	mac5380=	[HW,SCSI] Format:
			<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>

	mac53c9x=	[HW,SCSI] Format:
			<num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>

	machvec=	[IA64] Force the use of a particular machine-vector
			(machvec) in a generic kernel.
			Example: machvec=hpzx1_swiotlb

	max_loop=	[LOOP] Maximum number of loopback devices that can
			be mounted
			Format: <1-256>

	maxcpus=	[SMP] Maximum number of processors that	an SMP kernel
			should make use of

	max_addr=[KMG]	[KNL,BOOT,ia64] All physical memory greater than or
			equal to this physical address is ignored.

	max_luns=	[SCSI] Maximum number of LUNs to probe.
			Should be between 1 and 2^32-1.

	max_report_luns=
			[SCSI] Maximum number of LUNs received.
			Should be between 1 and 16384.

	mca-pentium	[BUGS=IA-32]

	mcatest=	[IA-64]

	mcd=		[HW,CD]
			Format: <port>,<irq>,<mitsumi_bug_93_wait>

	mcdx=		[HW,CD]

	mce		[IA-32] Machine Check Exception

	md=		[HW] RAID subsystems devices and level
			See Documentation/md.txt.

	mdacon=		[MDA]
			Format: <first>,<last>
			Specifies range of consoles to be captured by the MDA.

	mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory
			Amount of memory to be used when the kernel is not able
			to see the whole system memory or for test.
			[IA-32] Use together with memmap= to avoid physical
			address space collisions. Without memmap= PCI devices
			could be placed at addresses belonging to unused RAM.

	mem=nopentium	[BUGS=IA-32] Disable usage of 4MB pages for kernel
			memory.

	memmap=exactmap	[KNL,IA-32,X86_64] Enable setting of an exact
			E820 memory map, as specified by the user.
			Such memmap=exactmap lines can be constructed based on
			BIOS output or other requirements. See the memmap=nn@ss
			option description.

	memmap=nn[KMG]@ss[KMG]
			[KNL] Force usage of a specific region of memory
			Region of memory to be used, from ss to ss+nn.

	memmap=nn[KMG]#ss[KMG]
			[KNL,ACPI] Mark specific memory as ACPI data.
			Region of memory to be used, from ss to ss+nn.

	memmap=nn[KMG]$ss[KMG]
			[KNL,ACPI] Mark specific memory as reserved.
			Region of memory to be used, from ss to ss+nn.

	meye.*=		[HW] Set MotionEye Camera parameters
			See Documentation/video4linux/meye.txt.

	mga=		[HW,DRM]

	migration_cost=
			[KNL,SMP] debug: override scheduler migration costs
			Format: <level-1-usecs>,<level-2-usecs>,...
			This debugging option can be used to override the
			default scheduler migration cost matrix. The numbers
			are indexed by 'CPU domain distance'.
			E.g. migration_cost=1000,2000,3000 on an SMT NUMA
			box will set up an intra-core migration cost of
			1 msec, an inter-core migration cost of 2 msecs,
			and an inter-node migration cost of 3 msecs.

			WARNING: using the wrong values here can break
			scheduler performance, so it's only for scheduler
			development purposes, not production environments.

	migration_debug=
			[KNL,SMP] migration cost auto-detect verbosity
			Format=<0|1|2>
			If a system's migration matrix reported at bootup
			seems erroneous then this option can be used to
			increase verbosity of the detection process.
			We default to 0 (no extra messages), 1 will print
			some more information, and 2 will be really
			verbose (probably only useful if you also have a
			serial console attached to the system).

	migration_factor=
			[KNL,SMP] multiply/divide migration costs by a factor
			Format=<percent>
			This debug option can be used to proportionally
			increase or decrease the auto-detected migration
			costs for all entries of the migration matrix.
			E.g. migration_factor=150 will increase migration
			costs by 50%. (and thus the scheduler will be less
			eager migrating cache-hot tasks)
			migration_factor=80 will decrease migration costs
			by 20%. (thus the scheduler will be more eager to
			migrate tasks)

			WARNING: using the wrong values here can break
			scheduler performance, so it's only for scheduler
			development purposes, not production environments.

	mousedev.tap_time=
			[MOUSE] Maximum time between finger touching and
			leaving touchpad surface for touch to be considered
			a tap and be reported as a left button click (for
			touchpads working in absolute mode only).
			Format: <msecs>
	mousedev.xres=	[MOUSE] Horizontal screen resolution, used for devices
			reporting absolute coordinates, such as tablets
	mousedev.yres=	[MOUSE] Vertical screen resolution, used for devices
			reporting absolute coordinates, such as tablets

	mpu401=		[HW,OSS]
			Format: <io>,<irq>

	MTD_Partition=	[MTD]
			Format: <name>,<region-number>,<size>,<offset>

	MTD_Region=	[MTD] Format:
			<name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]

	mtdparts=	[MTD]
			See drivers/mtd/cmdline.c.

	mtouchusb.raw_coordinates=
			[HW] Make the MicroTouch USB driver use raw coordinates
			('y', default) or cooked coordinates ('n')

	n2=		[NET] SDL Inc. RISCom/N2 synchronous serial card

	NCR_D700=	[HW,SCSI]
			See header of drivers/scsi/NCR_D700.c.

	ncr5380=	[HW,SCSI]

	ncr53c400=	[HW,SCSI]

	ncr53c400a=	[HW,SCSI]

	ncr53c406a=	[HW,SCSI]

	ncr53c8xx=	[HW,SCSI]

	netdev=		[NET] Network devices parameters
			Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
			Note that mem_start is often overloaded to mean
			something different and driver-specific.
			This usage is only documented in each driver source
			file if at all.

	nfsaddrs=	[NFS]
			See Documentation/nfsroot.txt.

	nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
			See Documentation/nfsroot.txt.

	nfs.callback_tcpport=
			[NFS] set the TCP port on which the NFSv4 callback
			channel should listen.

	nfs.idmap_cache_timeout=
			[NFS] set the maximum lifetime for idmapper cache
			entries.

	nmi_watchdog=	[KNL,BUGS=IA-32] Debugging features for SMP kernels

	no387		[BUGS=IA-32] Tells the kernel to use the 387 maths
			emulation library even if a 387 maths coprocessor
			is present.

	noaliencache	[MM, NUMA] Disables the allcoation of alien caches in
			the slab allocator.  Saves per-node memory, but will
			impact performance on real NUMA hardware.

	noalign		[KNL,ARM]

	noapic		[SMP,APIC] Tells the kernel to not make use of any
			IOAPICs that may be present in the system.

	noasync		[HW,M68K] Disables async and sync negotiation for
			all devices.

	nobats		[PPC] Do not use BATs for mapping kernel lowmem
			on "Classic" PPC cores.

	nocache		[ARM]

	nodelayacct	[KNL] Disable per-task delay accounting

	nodisconnect	[HW,SCSI,M68K] Disables SCSI disconnects.

	noexec		[IA-64]

	noexec		[IA-32,X86-64]
			noexec=on: enable non-executable mappings (default)
			noexec=off: disable nn-executable mappings

	nofxsr		[BUGS=IA-32] Disables x86 floating point extended
			register save and restore. The kernel will only save
			legacy floating-point registers on task switch.

	nohlt		[BUGS=ARM]

	no-hlt		[BUGS=IA-32] Tells the kernel that the hlt
			instruction doesn't work correctly and not to
			use it.

	nohalt		[IA-64] Tells the kernel not to use the power saving
			function PAL_HALT_LIGHT when idle. This increases
			power-consumption. On the positive side, it reduces
			interrupt wake-up latency, which may improve performance
			in certain environments such as networked servers or
			real-time systems.

	noirqdebug	[IA-32] Disables the code which attempts to detect and
			disable unhandled interrupt sources.

	noisapnp	[ISAPNP] Disables ISA PnP code.

	noinitrd	[RAM] Tells the kernel not to load any configured
			initial RAM disk.

	nointroute	[IA-64]

	nolapic		[IA-32,APIC] Do not enable or use the local APIC.

	noltlbs		[PPC] Do not use large page/tlb entries for kernel
			lowmem mapping on PPC40x.

	nomca		[IA-64] Disable machine check abort handling

	nomce		[IA-32] Machine Check Exception

	noresidual	[PPC] Don't use residual data on PReP machines.

	noresume	[SWSUSP] Disables resume and restores original swap
			space.

	no-scroll	[VGA] Disables scrollback.
			This is required for the Braillex ib80-piezo Braille
			reader made by F.H. Papenmeier (Germany).

	nosbagart	[IA-64]

	nosep		[BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.

	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel.

	nosync		[HW,M68K] Disables sync negotiation for all devices.

	notsc		[BUGS=IA-32] Disable Time Stamp Counter

	nousb		[USB] Disable the USB subsystem

	nowb		[ARM]

	nr_uarts=	[SERIAL] maximum number of UARTs to be registered.

	opl3=		[HW,OSS]
			Format: <io>

	opl3sa2=	[HW,OSS] Format:
			<io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]

	oprofile.timer=	[HW]
			Use timer interrupt instead of performance counters

	optcd=		[HW,CD]
			Format: <io>

	osst=		[HW,SCSI] SCSI Tape Driver
			Format: <buffer_size>,<write_threshold>
			See also Documentation/scsi/st.txt.

	panic=		[KNL] Kernel behaviour on panic
			Format: <timeout>

	parkbd.port=	[HW] Parallel port number the keyboard adapter is
			connected to, default is 0.
			Format: <parport#>
	parkbd.mode=	[HW] Parallel port keyboard adapter mode of operation,
			0 for XT, 1 for AT (default is AT).
			Format: <mode>

	parport=	[HW,PPT] Specify parallel ports. 0 disables.
			Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
			Use 'auto' to force the driver to use any
			IRQ/DMA settings detected (the default is to
			ignore detected IRQ/DMA settings because of
			possible conflicts). You can specify the base
			address, IRQ, and DMA settings; IRQ and DMA
			should be numbers, or 'auto' (for using detected
			settings on that particular port), or 'nofifo'
			(to avoid using a FIFO even if it is detected).
			Parallel ports are assigned in the order they
			are specified on the command line, starting
			with parport0.

	parport_init_mode=	[HW,PPT]
			Configure VIA parallel port to operate in
			a specific mode. This is necessary on Pegasos
			computer where firmware has no options for setting
			up parallel port mode and sets it to spp.
			Currently this function knows 686a and 8231 chips.
			Format: [spp|ps2|epp|ecp|ecpepp]

	pas2=		[HW,OSS] Format:
			<io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>

	pas16=		[HW,SCSI]
			See header of drivers/scsi/pas16.c.

	pause_on_oops=
			Halt all CPUs after the first oops has been printed for
			the specified number of seconds.  This is to be used if
			your oopses keep scrolling off the screen.

	pcbit=		[HW,ISDN]

	pcd.		[PARIDE]
			See header of drivers/block/paride/pcd.c.
			See also Documentation/paride.txt.

	pci=option[,option...]	[PCI] various PCI subsystem options:
		off		[IA-32] don't probe for the PCI bus
		bios		[IA-32] force use of PCI BIOS, don't access
				the hardware directly. Use this if your machine
				has a non-standard PCI host bridge.
		nobios		[IA-32] disallow use of PCI BIOS, only direct
				hardware access methods are allowed. Use this
				if you experience crashes upon bootup and you
				suspect they are caused by the BIOS.
		conf1		[IA-32] Force use of PCI Configuration
				Mechanism 1.
		conf2		[IA-32] Force use of PCI Configuration
				Mechanism 2.
		nommconf	[IA-32,X86_64] Disable use of MMCONFIG for PCI
				Configuration
		nomsi		[MSI] If the PCI_MSI kernel config parameter is
				enabled, this kernel boot option can be used to
				disable the use of MSI interrupts system-wide.
		nosort		[IA-32] Don't sort PCI devices according to
				order given by the PCI BIOS. This sorting is
				done to get a device order compatible with
				older kernels.
		biosirq		[IA-32] Use PCI BIOS calls to get the interrupt
				routing table. These calls are known to be buggy
				on several machines and they hang the machine
				when used, but on other computers it's the only
				way to get the interrupt routing table. Try
				this option if the kernel is unable to allocate
				IRQs or discover secondary PCI buses on your
				motherboard.
		rom		[IA-32] Assign address space to expansion ROMs.
				Use with caution as certain devices share
				address decoders between ROMs and other
				resources.
		irqmask=0xMMMM	[IA-32] Set a bit mask of IRQs allowed to be
				assigned automatically to PCI devices. You can
				make the kernel exclude IRQs of your ISA cards
				this way.
		pirqaddr=0xAAAAA	[IA-32] Specify the physical address
				of the PIRQ table (normally generated
				by the BIOS) if it is outside the
				F0000h-100000h range.
		lastbus=N	[IA-32] Scan all buses thru bus #N. Can be
				useful if the kernel is unable to find your
				secondary buses and you want to tell it
				explicitly which ones they are.
		assign-busses	[IA-32] Always assign all PCI bus
				numbers ourselves, overriding
				whatever the firmware may have done.
		usepirqmask	[IA-32] Honor the possible IRQ mask stored
				in the BIOS $PIR table. This is needed on
				some systems with broken BIOSes, notably
				some HP Pavilion N5400 and Omnibook XE3
				notebooks. This will have no effect if ACPI
				IRQ routing is enabled.
		noacpi		[IA-32] Do not use ACPI for IRQ routing
				or for PCI scanning.
		routeirq	Do IRQ routing for all PCI devices.
				This is normally done in pci_enable_device(),
				so this option is a temporary workaround
				for broken drivers that don't call it.
		firmware	[ARM] Do not re-enumerate the bus but instead
				just use the configuration from the
				bootloader. This is currently used on
				IXP2000 systems where the bus has to be
				configured a certain way for adjunct CPUs.
		noearly		[X86] Don't do any early type 1 scanning.
				This might help on some broken boards which
				machine check when some devices' config space
				is read. But various workarounds are disabled
				and some IOMMU drivers will not work.
		bfsort		Sort PCI devices into breadth-first order.
				This sorting is done to get a device
				order compatible with older (<= 2.4) kernels.
		nobfsort	Don't sort PCI devices into breadth-first order.

	pcmv=		[HW,PCMCIA] BadgePAD 4

	pd.		[PARIDE]
			See Documentation/paride.txt.

	pdcchassis=	[PARISC,HW] Disable/Enable PDC Chassis Status codes at
			boot time.
			Format: { 0 | 1 }
			See arch/parisc/kernel/pdc_chassis.c

	pf.		[PARIDE]
			See Documentation/paride.txt.

	pg.		[PARIDE]
			See Documentation/paride.txt.

	pirq=		[SMP,APIC] Manual mp-table setup
			See Documentation/i386/IO-APIC.txt.

	plip=		[PPT,NET] Parallel port network link
			Format: { parport<nr> | timid | 0 }
			See also Documentation/parport.txt.

	pnpacpi=	[ACPI]
			{ off }

	pnpbios=	[ISAPNP]
			{ on | off | curr | res | no-curr | no-res }

	pnp_reserve_irq=
			[ISAPNP] Exclude IRQs for the autoconfiguration

	pnp_reserve_dma=
			[ISAPNP] Exclude DMAs for the autoconfiguration

	pnp_reserve_io=	[ISAPNP] Exclude I/O ports for the autoconfiguration
			Ranges are in pairs (I/O port base and size).

	pnp_reserve_mem=
			[ISAPNP] Exclude memory regions for the
			autoconfiguration.
			Ranges are in pairs (memory base and size).

	profile=	[KNL] Enable kernel profiling via /proc/profile
			Format: [schedule,]<number>
			Param: "schedule" - profile schedule points.
			Param: <number> - step/bucket size as a power of 2 for
				statistical time based profiling.

	processor.max_cstate=	[HW,ACPI]
			Limit processor to maximum C-state
			max_cstate=9 overrides any DMI blacklist limit.

	processor.nocst	[HW,ACPI]
			Ignore the _CST method to determine C-states,
			instead using the legacy FADT method

	prompt_ramdisk=	[RAM] List of RAM disks to prompt for floppy disk
			before loading.
			See Documentation/ramdisk.txt.

	psmouse.proto=	[HW,MOUSE] Highest PS2 mouse protocol extension to
			probe for; one of (bare|imps|exps|lifebook|any).
	psmouse.rate=	[HW,MOUSE] Set desired mouse report rate, in reports
			per second.
	psmouse.resetafter=	[HW,MOUSE]
			Try to reset the device after so many bad packets
			(0 = never).
	psmouse.resolution=
			[HW,MOUSE] Set desired mouse resolution, in dpi.
	psmouse.smartscroll=
			[HW,MOUSE] Controls Logitech smartscroll autorepeat.
			0 = disabled, 1 = enabled (default).

	pss=		[HW,OSS] Personal Sound System (ECHO ESC614)
			Format:
			<io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>

	pt.		[PARIDE]
			See Documentation/paride.txt.

	quiet		[KNL] Disable most log messages

	r128=		[HW,DRM]

	raid=		[HW,RAID]
			See Documentation/md.txt.

	ramdisk=	[RAM] Sizes of RAM disks in kilobytes [deprecated]
			See Documentation/ramdisk.txt.

	ramdisk_blocksize=	[RAM]
			See Documentation/ramdisk.txt.

	ramdisk_size=	[RAM] Sizes of RAM disks in kilobytes
			New name for the ramdisk parameter.
			See Documentation/ramdisk.txt.

	rcu.blimit=	[KNL,BOOT] Set maximum number of finished
			RCU callbacks to process in one batch.

	rcu.qhimark=	[KNL,BOOT] Set threshold of queued
			RCU callbacks over which batch limiting is disabled.

	rcu.qlowmark=	[KNL,BOOT] Set threshold of queued
			RCU callbacks below which batch limiting is re-enabled.

	rdinit=		[KNL]
			Format: <full_path>
			Run specified binary instead of /init from the ramdisk,
			used for early userspace startup. See initrd.

	reboot=		[BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
			Format: <reboot_mode>[,<reboot_mode2>[,...]]
			See arch/*/kernel/reboot.c or arch/*/kernel/process.c			

	reserve=	[KNL,BUGS] Force the kernel to ignore some iomem area

	reservetop=	[IA-32]
			Format: nn[KMG]
			Reserves a hole at the top of the kernel virtual
			address space.

	reset_devices	[KNL] Force drivers to reset the underlying device
			during initialization.

	resume=		[SWSUSP]
			Specify the partition device for software suspend

	resume_offset=	[SWSUSP]
			Specify the offset from the beginning of the partition
			given by "resume=" at which the swap header is located,
			in <PAGE_SIZE> units (needed only for swap files).
			See  Documentation/power/swsusp-and-swap-files.txt

	rhash_entries=	[KNL,NET]
			Set number of hash buckets for route cache

	riscom8=	[HW,SERIAL]
			Format: <io_board1>[,<io_board2>[,...<io_boardN>]]

	ro		[KNL] Mount root device read-only on boot

	root=		[KNL] Root filesystem

	rootdelay=	[KNL] Delay (in seconds) to pause before attempting to
			mount the root filesystem

	rootflags=	[KNL] Set root filesystem mount option string

	rootfstype=	[KNL] Set root filesystem type

	rw		[KNL] Mount root device read-write on boot

	S		[KNL] Run init in single mode

	sa1100ir	[NET]
			See drivers/net/irda/sa1100_ir.c.

	sb=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>

	sbni=		[NET] Granch SBNI12 leased line adapter

	sbpcd=		[HW,CD] Soundblaster CD adapter
			Format: <io>,<type>
			See a comment before function sbpcd_setup() in
			drivers/cdrom/sbpcd.c.

	sc1200wdt=	[HW,WDT] SC1200 WDT (watchdog) driver
			Format: <io>[,<timeout>[,<isapnp>]]

	scsi_debug_*=	[SCSI]
			See drivers/scsi/scsi_debug.c.

	scsi_default_dev_flags=
			[SCSI] SCSI default device flags
			Format: <integer>

	scsi_dev_flags=	[SCSI] Black/white list entry for vendor and model
			Format: <vendor>:<model>:<flags>
			(flags are integer value)

	scsi_logging=	[SCSI]

	scsi_mod.scan=	[SCSI] sync (default) scans SCSI busses as they are
			discovered.  async scans them in kernel threads,
			allowing boot to proceed.  none ignores them, expecting
			user space to do the scan.

	selinux		[SELINUX] Disable or enable SELinux at boot time.
			Format: { "0" | "1" }
			See security/selinux/Kconfig help text.
			0 -- disable.
			1 -- enable.
			Default value is set via kernel config option.
			If enabled at boot time, /selinux/disable can be used
			later to disable prior to initial policy load.

	selinux_compat_net =
			[SELINUX] Set initial selinux_compat_net flag value.
                        Format: { "0" | "1" }
                        0 -- use new secmark-based packet controls
                        1 -- use legacy packet controls
                        Default value is 0 (preferred).
                        Value can be changed at runtime via
                        /selinux/compat_net.

	serialnumber	[BUGS=IA-32]

	sg_def_reserved_size=	[SCSI]

	shapers=	[NET]
			Maximal number of shapers.

	sim710=		[SCSI,HW]
			See header of drivers/scsi/sim710.c.

	simeth=		[IA-64]
	simscsi=

	sjcd=		[HW,CD]
			Format: <io>,<irq>,<dma>
			See header of drivers/cdrom/sjcd.c.

	slram=		[HW,MTD]

	smart2=		[HW]
			Format: <io1>[,<io2>[,...,<io8>]]

	snd-ad1816a=	[HW,ALSA]

	snd-ad1848=	[HW,ALSA]

	snd-ali5451=	[HW,ALSA]

	snd-als100=	[HW,ALSA]

	snd-als4000=	[HW,ALSA]

	snd-azt2320=	[HW,ALSA]

	snd-cmi8330=	[HW,ALSA]

	snd-cmipci=	[HW,ALSA]

	snd-cs4231=	[HW,ALSA]

	snd-cs4232=	[HW,ALSA]

	snd-cs4236=	[HW,ALSA]

	snd-cs4281=	[HW,ALSA]

	snd-cs46xx=	[HW,ALSA]

	snd-dt019x=	[HW,ALSA]

	snd-dummy=	[HW,ALSA]

	snd-emu10k1=	[HW,ALSA]

	snd-ens1370=	[HW,ALSA]

	snd-ens1371=	[HW,ALSA]

	snd-es968=	[HW,ALSA]

	snd-es1688=	[HW,ALSA]

	snd-es18xx=	[HW,ALSA]

	snd-es1938=	[HW,ALSA]

	snd-es1968=	[HW,ALSA]

	snd-fm801=	[HW,ALSA]

	snd-gusclassic=	[HW,ALSA]

	snd-gusextreme=	[HW,ALSA]

	snd-gusmax=	[HW,ALSA]

	snd-hdsp=	[HW,ALSA]

	snd-ice1712=	[HW,ALSA]

	snd-intel8x0=	[HW,ALSA]

	snd-interwave=	[HW,ALSA]

	snd-interwave-stb=
			[HW,ALSA]

	snd-korg1212=	[HW,ALSA]

	snd-maestro3=	[HW,ALSA]

	snd-mpu401=	[HW,ALSA]

	snd-mtpav=	[HW,ALSA]

	snd-nm256=	[HW,ALSA]

	snd-opl3sa2=	[HW,ALSA]

	snd-opti92x-ad1848=
			[HW,ALSA]

	snd-opti92x-cs4231=
			[HW,ALSA]

	snd-opti93x=	[HW,ALSA]

	snd-pmac=	[HW,ALSA]

	snd-rme32=	[HW,ALSA]

	snd-rme96=	[HW,ALSA]

	snd-rme9652=	[HW,ALSA]

	snd-sb8=	[HW,ALSA]

	snd-sb16=	[HW,ALSA]

	snd-sbawe=	[HW,ALSA]

	snd-serial=	[HW,ALSA]

	snd-sgalaxy=	[HW,ALSA]

	snd-sonicvibes=	[HW,ALSA]

	snd-sun-amd7930=
			[HW,ALSA]

	snd-sun-cs4231=	[HW,ALSA]

	snd-trident=	[HW,ALSA]

	snd-usb-audio=	[HW,ALSA,USB]

	snd-via82xx=	[HW,ALSA]

	snd-virmidi=	[HW,ALSA]

	snd-wavefront=	[HW,ALSA]

	snd-ymfpci=	[HW,ALSA]

	sonycd535=	[HW,CD]
			Format: <io>[,<irq>]

	sonypi.*=	[HW] Sony Programmable I/O Control Device driver
			See Documentation/sonypi.txt

	specialix=	[HW,SERIAL] Specialix multi-serial port adapter
			See Documentation/specialix.txt.

	spia_io_base=	[HW,MTD]
	spia_fio_base=
	spia_pedr=
	spia_peddr=

	sscape=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>

	st=		[HW,SCSI] SCSI tape parameters (buffers, etc.)
			See Documentation/scsi/st.txt.

	st0x=		[HW,SCSI]
			See header of drivers/scsi/seagate.c.

	sti=		[PARISC,HW]
			Format: <num>
			Set the STI (builtin display/keyboard on the HP-PARISC
			machines) console (graphic card) which should be used
			as the initial boot-console.
			See also comment in drivers/video/console/sticore.c.

	sti_font=	[HW]
			See comment in drivers/video/console/sticore.c.

	stifb=		[HW]
			Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]

	swiotlb=	[IA-64] Number of I/O TLB slabs

	switches=	[HW,M68k]

	sym53c416=	[HW,SCSI]
			See header of drivers/scsi/sym53c416.c.

	t128=		[HW,SCSI]
			See header of drivers/scsi/t128.c.

	tdfx=		[HW,DRM]

	thash_entries=	[KNL,NET]
			Set number of hash buckets for TCP connection

	time		Show timing data prefixed to each printk message line

	clocksource=	[GENERIC_TIME] Override the default clocksource
			Override the default clocksource and use the clocksource
			with the name specified.

	tipar.timeout=	[HW,PPT]
			Set communications timeout in tenths of a second
			(default 15).

	tipar.delay=	[HW,PPT]
			Set inter-bit delay in microseconds (default 10).

	tmc8xx=		[HW,SCSI]
			See header of drivers/scsi/seagate.c.

	tmscsim=	[HW,SCSI]
			See comment before function dc390_setup() in
			drivers/scsi/tmscsim.c.

	tp720=		[HW,PS2]

	trix=		[HW,OSS] MediaTrix AudioTrix Pro
			Format:
			<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>

	tsdev.xres=	[TS] Horizontal screen resolution.
	tsdev.yres=	[TS] Vertical screen resolution.

	turbografx.map[2|3]=	[HW,JOY]
			TurboGraFX parallel port interface
			Format:
			<port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
			See also Documentation/input/joystick-parport.txt

	u14-34f=	[HW,SCSI] UltraStor 14F/34F SCSI host adapter
			See header of drivers/scsi/u14-34f.c.

	uart401=	[HW,OSS]
			Format: <io>,<irq>

	uart6850=	[HW,OSS]
			Format: <io>,<irq>

	usbhid.mousepoll=
			[USBHID] The interval which mice are to be polled at.

	vdso=		[IA-32]
			vdso=1: enable VDSO (default)
			vdso=0: disable VDSO mapping

	video=		[FB] Frame buffer configuration
			See Documentation/fb/modedb.txt.

	vga=		[BOOT,IA-32] Select a particular video mode
			See Documentation/i386/boot.txt and
			Documentation/svga.txt.
			Use vga=ask for menu.
			This is actually a boot loader parameter; the value is
			passed to the kernel using a special protocol.

	vmalloc=nn[KMG]	[KNL,BOOT] Forces the vmalloc area to have an exact
			size of <nn>. This can be used to increase the
			minimum size (128MB on x86). It can also be used to
			decrease the size and leave more room for directly
			mapped kernel RAM.

	vmhalt=		[KNL,S390] Perform z/VM CP command after system halt.
			Format: <command>

	vmpanic=	[KNL,S390] Perform z/VM CP command after kernel panic.
			Format: <command>

	vmpoff=		[KNL,S390] Perform z/VM CP command after power off.
			Format: <command>

	waveartist=	[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>

	wd33c93=	[HW,SCSI]
			See header of drivers/scsi/wd33c93.c.

	wd7000=		[HW,SCSI]
			See header of drivers/scsi/wd7000.c.

	wdt=		[WDT] Watchdog
			See Documentation/watchdog/watchdog.txt.

	xd=		[HW,XT] Original XT pre-IDE (RLL encoded) disks.
	xd_geo=		See header of drivers/block/xd.c.

	xirc2ps_cs=	[NET,PCMCIA]
			Format:
			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]

	norandmaps	Don't use address space randomization
			Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space


______________________________________________________________________

TODO:

	Add documentation for ALSA options.
	Add more DRM drivers.