diff options
| -rw-r--r-- | drivers/acpi/acpica/aclocal.h | 22 | ||||
| -rw-r--r-- | drivers/acpi/acpica/acmacros.h | 29 | ||||
| -rw-r--r-- | drivers/acpi/acpica/utxface.c | 87 | ||||
| -rw-r--r-- | include/acpi/acbuffer.h | 192 | ||||
| -rw-r--r-- | include/acpi/acnames.h | 1 | ||||
| -rw-r--r-- | include/acpi/acpixf.h | 5 | ||||
| -rw-r--r-- | include/acpi/actbl.h | 12 | ||||
| -rw-r--r-- | include/acpi/actbl1.h | 12 | ||||
| -rw-r--r-- | include/acpi/actbl2.h | 12 | ||||
| -rw-r--r-- | include/acpi/actbl3.h | 12 |
10 files changed, 360 insertions, 24 deletions
diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h index 493529a3500..c816ee67509 100644 --- a/drivers/acpi/acpica/aclocal.h +++ b/drivers/acpi/acpica/aclocal.h @@ -707,15 +707,18 @@ union acpi_parse_value { u8 disasm_opcode; /* Subtype used for disassembly */\ char aml_op_name[16]) /* Op name (debug only) */ -#define ACPI_DASM_BUFFER 0x00 -#define ACPI_DASM_RESOURCE 0x01 -#define ACPI_DASM_STRING 0x02 -#define ACPI_DASM_UNICODE 0x03 -#define ACPI_DASM_EISAID 0x04 -#define ACPI_DASM_MATCHOP 0x05 -#define ACPI_DASM_LNOT_PREFIX 0x06 -#define ACPI_DASM_LNOT_SUFFIX 0x07 -#define ACPI_DASM_IGNORE 0x08 +/* Flags for disasm_flags field above */ + +#define ACPI_DASM_BUFFER 0x00 /* Buffer is a simple data buffer */ +#define ACPI_DASM_RESOURCE 0x01 /* Buffer is a Resource Descriptor */ +#define ACPI_DASM_STRING 0x02 /* Buffer is a ASCII string */ +#define ACPI_DASM_UNICODE 0x03 /* Buffer is a Unicode string */ +#define ACPI_DASM_PLD_METHOD 0x04 /* Buffer is a _PLD method bit-packed buffer */ +#define ACPI_DASM_EISAID 0x05 /* Integer is an EISAID */ +#define ACPI_DASM_MATCHOP 0x06 /* Parent opcode is a Match() operator */ +#define ACPI_DASM_LNOT_PREFIX 0x07 /* Start of a Lnot_equal (etc.) pair of opcodes */ +#define ACPI_DASM_LNOT_SUFFIX 0x08 /* End of a Lnot_equal (etc.) pair of opcodes */ +#define ACPI_DASM_IGNORE 0x09 /* Not used at this time */ /* * Generic operation (for example: If, While, Store) @@ -1025,6 +1028,7 @@ struct acpi_port_info { ****************************************************************************/ struct acpi_db_method_info { + acpi_handle method; acpi_handle main_thread_gate; acpi_handle thread_complete_gate; acpi_thread_id *threads; diff --git a/drivers/acpi/acpica/acmacros.h b/drivers/acpi/acpica/acmacros.h index 832b6198652..a7f68c47f51 100644 --- a/drivers/acpi/acpica/acmacros.h +++ b/drivers/acpi/acpica/acmacros.h @@ -277,10 +277,33 @@ /* Bitfields within ACPI registers */ -#define ACPI_REGISTER_PREPARE_BITS(val, pos, mask) ((val << pos) & mask) -#define ACPI_REGISTER_INSERT_VALUE(reg, pos, mask, val) reg = (reg & (~(mask))) | ACPI_REGISTER_PREPARE_BITS(val, pos, mask) +#define ACPI_REGISTER_PREPARE_BITS(val, pos, mask) \ + ((val << pos) & mask) -#define ACPI_INSERT_BITS(target, mask, source) target = ((target & (~(mask))) | (source & mask)) +#define ACPI_REGISTER_INSERT_VALUE(reg, pos, mask, val) \ + reg = (reg & (~(mask))) | ACPI_REGISTER_PREPARE_BITS(val, pos, mask) + +#define ACPI_INSERT_BITS(target, mask, source) \ + target = ((target & (~(mask))) | (source & mask)) + +/* Generic bitfield macros and masks */ + +#define ACPI_GET_BITS(source_ptr, position, mask) \ + ((*source_ptr >> position) & mask) + +#define ACPI_SET_BITS(target_ptr, position, mask, value) \ + (*target_ptr |= ((value & mask) << position)) + +#define ACPI_1BIT_MASK 0x00000001 +#define ACPI_2BIT_MASK 0x00000003 +#define ACPI_3BIT_MASK 0x00000007 +#define ACPI_4BIT_MASK 0x0000000F +#define ACPI_5BIT_MASK 0x0000001F +#define ACPI_6BIT_MASK 0x0000003F +#define ACPI_7BIT_MASK 0x0000007F +#define ACPI_8BIT_MASK 0x000000FF +#define ACPI_16BIT_MASK 0x0000FFFF +#define ACPI_24BIT_MASK 0x00FFFFFF /* * An object of type struct acpi_namespace_node can appear in some contexts diff --git a/drivers/acpi/acpica/utxface.c b/drivers/acpi/acpica/utxface.c index 667229dbcba..b09632b4f5b 100644 --- a/drivers/acpi/acpica/utxface.c +++ b/drivers/acpi/acpica/utxface.c @@ -418,3 +418,90 @@ acpi_check_address_range(acpi_adr_space_type space_id, ACPI_EXPORT_SYMBOL(acpi_check_address_range) #endif /* !ACPI_ASL_COMPILER */ +/******************************************************************************* + * + * FUNCTION: acpi_decode_pld_buffer + * + * PARAMETERS: in_buffer - Buffer returned by _PLD method + * length - Length of the in_buffer + * return_buffer - Where the decode buffer is returned + * + * RETURN: Status and the decoded _PLD buffer. User must deallocate + * the buffer via ACPI_FREE. + * + * DESCRIPTION: Decode the bit-packed buffer returned by the _PLD method into + * a local struct that is much more useful to an ACPI driver. + * + ******************************************************************************/ +acpi_status +acpi_decode_pld_buffer(u8 *in_buffer, + acpi_size length, struct acpi_pld_info ** return_buffer) +{ + struct acpi_pld_info *pld_info; + u32 *buffer = ACPI_CAST_PTR(u32, in_buffer); + u32 dword; + + /* Parameter validation */ + + if (!in_buffer || !return_buffer || (length < 16)) { + return (AE_BAD_PARAMETER); + } + + pld_info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_pld_info)); + if (!pld_info) { + return (AE_NO_MEMORY); + } + + /* First 32-bit DWord */ + + ACPI_MOVE_32_TO_32(&dword, &buffer[0]); + pld_info->revision = ACPI_PLD_GET_REVISION(&dword); + pld_info->ignore_color = ACPI_PLD_GET_IGNORE_COLOR(&dword); + pld_info->color = ACPI_PLD_GET_COLOR(&dword); + + /* Second 32-bit DWord */ + + ACPI_MOVE_32_TO_32(&dword, &buffer[1]); + pld_info->width = ACPI_PLD_GET_WIDTH(&dword); + pld_info->height = ACPI_PLD_GET_HEIGHT(&dword); + + /* Third 32-bit DWord */ + + ACPI_MOVE_32_TO_32(&dword, &buffer[2]); + pld_info->user_visible = ACPI_PLD_GET_USER_VISIBLE(&dword); + pld_info->dock = ACPI_PLD_GET_DOCK(&dword); + pld_info->lid = ACPI_PLD_GET_LID(&dword); + pld_info->panel = ACPI_PLD_GET_PANEL(&dword); + pld_info->vertical_position = ACPI_PLD_GET_VERTICAL(&dword); + pld_info->horizontal_position = ACPI_PLD_GET_HORIZONTAL(&dword); + pld_info->shape = ACPI_PLD_GET_SHAPE(&dword); + pld_info->group_orientation = ACPI_PLD_GET_ORIENTATION(&dword); + pld_info->group_token = ACPI_PLD_GET_TOKEN(&dword); + pld_info->group_position = ACPI_PLD_GET_POSITION(&dword); + pld_info->bay = ACPI_PLD_GET_BAY(&dword); + + /* Fourth 32-bit DWord */ + + ACPI_MOVE_32_TO_32(&dword, &buffer[3]); + pld_info->ejectable = ACPI_PLD_GET_EJECTABLE(&dword); + pld_info->ospm_eject_required = ACPI_PLD_GET_OSPM_EJECT(&dword); + pld_info->cabinet_number = ACPI_PLD_GET_CABINET(&dword); + pld_info->card_cage_number = ACPI_PLD_GET_CARD_CAGE(&dword); + pld_info->reference = ACPI_PLD_GET_REFERENCE(&dword); + pld_info->rotation = ACPI_PLD_GET_ROTATION(&dword); + pld_info->order = ACPI_PLD_GET_ORDER(&dword); + + if (length >= ACPI_PLD_BUFFER_SIZE) { + + /* Fifth 32-bit DWord (Revision 2 of _PLD) */ + + ACPI_MOVE_32_TO_32(&dword, &buffer[4]); + pld_info->vertical_offset = ACPI_PLD_GET_VERT_OFFSET(&dword); + pld_info->horizontal_offset = ACPI_PLD_GET_HORIZ_OFFSET(&dword); + } + + *return_buffer = pld_info; + return (AE_OK); +} + +ACPI_EXPORT_SYMBOL(acpi_decode_pld_buffer) diff --git a/include/acpi/acbuffer.h b/include/acpi/acbuffer.h new file mode 100644 index 00000000000..2c3b44789f9 --- /dev/null +++ b/include/acpi/acbuffer.h @@ -0,0 +1,192 @@ +/****************************************************************************** + * + * Name: acbuffer.h - Support for buffers returned by ACPI predefined names + * + *****************************************************************************/ + +/* + * Copyright (C) 2000 - 2012, Intel Corp. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce at minimum a disclaimer + * substantially similar to the "NO WARRANTY" disclaimer below + * ("Disclaimer") and any redistribution must be conditioned upon + * including a substantially similar Disclaimer requirement for further + * binary redistribution. + * 3. Neither the names of the above-listed copyright holders nor the names + * of any contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * Alternatively, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2 as published by the Free + * Software Foundation. + * + * NO WARRANTY + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGES. + */ + +#ifndef __ACBUFFER_H__ +#define __ACBUFFER_H__ + +/* + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 + */ + +/* + * Formatted _PLD return value. The minimum size is a package containing + * one buffer. + * Revision 1: Buffer is 16 bytes (128 bits) + * Revision 2: Buffer is 20 bytes (160 bits) + * + * Note: This structure is returned from the acpi_decode_pld_buffer + * interface. + */ +struct acpi_pld_info { + u8 revision; + u8 ignore_color; + u32 color; + u16 width; + u16 height; + u8 user_visible; + u8 dock; + u8 lid; + u8 panel; + u8 vertical_position; + u8 horizontal_position; + u8 shape; + u8 group_orientation; + u8 group_token; + u8 group_position; + u8 bay; + u8 ejectable; + u8 ospm_eject_required; + u8 cabinet_number; + u8 card_cage_number; + u8 reference; + u8 rotation; + u8 order; + u8 reserved; + u16 vertical_offset; + u16 horizontal_offset; +}; + +/* + * Macros to: + * 1) Convert a _PLD buffer to internal struct acpi_pld_info format - ACPI_PLD_GET* + * (Used by acpi_decode_pld_buffer) + * 2) Construct a _PLD buffer - ACPI_PLD_SET* + * (Intended for BIOS use only) + */ +#define ACPI_PLD_REV1_BUFFER_SIZE 16 /* For Revision 1 of the buffer (From ACPI spec) */ +#define ACPI_PLD_BUFFER_SIZE 20 /* For Revision 2 of the buffer (From ACPI spec) */ + +/* First 32-bit dword, bits 0:32 */ + +#define ACPI_PLD_GET_REVISION(dword) ACPI_GET_BITS (dword, 0, ACPI_7BIT_MASK) +#define ACPI_PLD_SET_REVISION(dword,value) ACPI_SET_BITS (dword, 0, ACPI_7BIT_MASK, value) /* Offset 0, Len 7 */ + +#define ACPI_PLD_GET_IGNORE_COLOR(dword) ACPI_GET_BITS (dword, 7, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_IGNORE_COLOR(dword,value) ACPI_SET_BITS (dword, 7, ACPI_1BIT_MASK, value) /* Offset 7, Len 1 */ + +#define ACPI_PLD_GET_COLOR(dword) ACPI_GET_BITS (dword, 8, ACPI_24BIT_MASK) +#define ACPI_PLD_SET_COLOR(dword,value) ACPI_SET_BITS (dword, 8, ACPI_24BIT_MASK, value) /* Offset 8, Len 24 */ + +/* Second 32-bit dword, bits 33:63 */ + +#define ACPI_PLD_GET_WIDTH(dword) ACPI_GET_BITS (dword, 0, ACPI_16BIT_MASK) +#define ACPI_PLD_SET_WIDTH(dword,value) ACPI_SET_BITS (dword, 0, ACPI_16BIT_MASK, value) /* Offset 32+0=32, Len 16 */ + +#define ACPI_PLD_GET_HEIGHT(dword) ACPI_GET_BITS (dword, 16, ACPI_16BIT_MASK) +#define ACPI_PLD_SET_HEIGHT(dword,value) ACPI_SET_BITS (dword, 16, ACPI_16BIT_MASK, value) /* Offset 32+16=48, Len 16 */ + +/* Third 32-bit dword, bits 64:95 */ + +#define ACPI_PLD_GET_USER_VISIBLE(dword) ACPI_GET_BITS (dword, 0, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_USER_VISIBLE(dword,value) ACPI_SET_BITS (dword, 0, ACPI_1BIT_MASK, value) /* Offset 64+0=64, Len 1 */ + +#define ACPI_PLD_GET_DOCK(dword) ACPI_GET_BITS (dword, 1, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_DOCK(dword,value) ACPI_SET_BITS (dword, 1, ACPI_1BIT_MASK, value) /* Offset 64+1=65, Len 1 */ + +#define ACPI_PLD_GET_LID(dword) ACPI_GET_BITS (dword, 2, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_LID(dword,value) ACPI_SET_BITS (dword, 2, ACPI_1BIT_MASK, value) /* Offset 64+2=66, Len 1 */ + +#define ACPI_PLD_GET_PANEL(dword) ACPI_GET_BITS (dword, 3, ACPI_3BIT_MASK) +#define ACPI_PLD_SET_PANEL(dword,value) ACPI_SET_BITS (dword, 3, ACPI_3BIT_MASK, value) /* Offset 64+3=67, Len 3 */ + +#define ACPI_PLD_GET_VERTICAL(dword) ACPI_GET_BITS (dword, 6, ACPI_2BIT_MASK) +#define ACPI_PLD_SET_VERTICAL(dword,value) ACPI_SET_BITS (dword, 6, ACPI_2BIT_MASK, value) /* Offset 64+6=70, Len 2 */ + +#define ACPI_PLD_GET_HORIZONTAL(dword) ACPI_GET_BITS (dword, 8, ACPI_2BIT_MASK) +#define ACPI_PLD_SET_HORIZONTAL(dword,value) ACPI_SET_BITS (dword, 8, ACPI_2BIT_MASK, value) /* Offset 64+8=72, Len 2 */ + +#define ACPI_PLD_GET_SHAPE(dword) ACPI_GET_BITS (dword, 10, ACPI_4BIT_MASK) +#define ACPI_PLD_SET_SHAPE(dword,value) ACPI_SET_BITS (dword, 10, ACPI_4BIT_MASK, value) /* Offset 64+10=74, Len 4 */ + +#define ACPI_PLD_GET_ORIENTATION(dword) ACPI_GET_BITS (dword, 14, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_ORIENTATION(dword,value) ACPI_SET_BITS (dword, 14, ACPI_1BIT_MASK, value) /* Offset 64+14=78, Len 1 */ + +#define ACPI_PLD_GET_TOKEN(dword) ACPI_GET_BITS (dword, 15, ACPI_8BIT_MASK) +#define ACPI_PLD_SET_TOKEN(dword,value) ACPI_SET_BITS (dword, 15, ACPI_8BIT_MASK, value) /* Offset 64+15=79, Len 8 */ + +#define ACPI_PLD_GET_POSITION(dword) ACPI_GET_BITS (dword, 23, ACPI_8BIT_MASK) +#define ACPI_PLD_SET_POSITION(dword,value) ACPI_SET_BITS (dword, 23, ACPI_8BIT_MASK, value) /* Offset 64+23=87, Len 8 */ + +#define ACPI_PLD_GET_BAY(dword) ACPI_GET_BITS (dword, 31, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_BAY(dword,value) ACPI_SET_BITS (dword, 31, ACPI_1BIT_MASK, value) /* Offset 64+31=95, Len 1 */ + +/* Fourth 32-bit dword, bits 96:127 */ + +#define ACPI_PLD_GET_EJECTABLE(dword) ACPI_GET_BITS (dword, 0, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_EJECTABLE(dword,value) ACPI_SET_BITS (dword, 0, ACPI_1BIT_MASK, value) /* Offset 96+0=96, Len 1 */ + +#define ACPI_PLD_GET_OSPM_EJECT(dword) ACPI_GET_BITS (dword, 1, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_OSPM_EJECT(dword,value) ACPI_SET_BITS (dword, 1, ACPI_1BIT_MASK, value) /* Offset 96+1=97, Len 1 */ + +#define ACPI_PLD_GET_CABINET(dword) ACPI_GET_BITS (dword, 2, ACPI_8BIT_MASK) +#define ACPI_PLD_SET_CABINET(dword,value) ACPI_SET_BITS (dword, 2, ACPI_8BIT_MASK, value) /* Offset 96+2=98, Len 8 */ + +#define ACPI_PLD_GET_CARD_CAGE(dword) ACPI_GET_BITS (dword, 10, ACPI_8BIT_MASK) +#define ACPI_PLD_SET_CARD_CAGE(dword,value) ACPI_SET_BITS (dword, 10, ACPI_8BIT_MASK, value) /* Offset 96+10=106, Len 8 */ + +#define ACPI_PLD_GET_REFERENCE(dword) ACPI_GET_BITS (dword, 18, ACPI_1BIT_MASK) +#define ACPI_PLD_SET_REFERENCE(dword,value) ACPI_SET_BITS (dword, 18, ACPI_1BIT_MASK, value) /* Offset 96+18=114, Len 1 */ + +#define ACPI_PLD_GET_ROTATION(dword) ACPI_GET_BITS (dword, 19, ACPI_4BIT_MASK) +#define ACPI_PLD_SET_ROTATION(dword,value) ACPI_SET_BITS (dword, 19, ACPI_4BIT_MASK, value) /* Offset 96+19=115, Len 4 */ + +#define ACPI_PLD_GET_ORDER(dword) ACPI_GET_BITS (dword, 23, ACPI_5BIT_MASK) +#define ACPI_PLD_SET_ORDER(dword,value) ACPI_SET_BITS (dword, 23, ACPI_5BIT_MASK, value) /* Offset 96+23=119, Len 5 */ + +/* Fifth 32-bit dword, bits 128:159 (Revision 2 of _PLD only) */ + +#define ACPI_PLD_GET_VERT_OFFSET(dword) ACPI_GET_BITS (dword, 0, ACPI_16BIT_MASK) +#define ACPI_PLD_SET_VERT_OFFSET(dword,value) ACPI_SET_BITS (dword, 0, ACPI_16BIT_MASK, value) /* Offset 128+0=128, Len 16 */ + +#define ACPI_PLD_GET_HORIZ_OFFSET(dword) ACPI_GET_BITS (dword, 16, ACPI_16BIT_MASK) +#define ACPI_PLD_SET_HORIZ_OFFSET(dword,value) ACPI_SET_BITS (dword, 16, ACPI_16BIT_MASK, value) /* Offset 128+16=144, Len 16 */ + +#endif /* ACBUFFER_H */ diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h index d2f61dd2d72..745dd24e3cb 100644 --- a/include/acpi/acnames.h +++ b/include/acpi/acnames.h @@ -63,6 +63,7 @@ #define METHOD_NAME__PRW "_PRW" #define METHOD_NAME__SRS "_SRS" #define METHOD_NAME__CBA "_CBA" +#define METHOD_NAME__PLD "_PLD" /* Method names - these methods must appear at the namespace root */ diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index 26a92fc28a5..270517d6b1b 100644 --- a/include/acpi/acpixf.h +++ b/include/acpi/acpixf.h @@ -52,6 +52,7 @@ #include "acconfig.h" #include "actypes.h" #include "actbl.h" +#include "acbuffer.h" extern u8 acpi_gbl_permanent_mmap; @@ -144,6 +145,10 @@ acpi_check_address_range(acpi_adr_space_type space_id, acpi_physical_address address, acpi_size length, u8 warn); +acpi_status +acpi_decode_pld_buffer(u8 *in_buffer, + acpi_size length, struct acpi_pld_info **return_buffer); + /* * ACPI Memory management */ diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h index d54e3580b7d..4f94b1d812d 100644 --- a/include/acpi/actbl.h +++ b/include/acpi/actbl.h @@ -79,9 +79,15 @@ #pragma pack(1) /* - * Note about bitfields: The u8 type is used for bitfields in ACPI tables. - * This is the only type that is even remotely portable. Anything else is not - * portable, so do not use any other bitfield types. + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 */ /******************************************************************************* diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h index 300d14e7c5d..c41d6f96ed7 100644 --- a/include/acpi/actbl1.h +++ b/include/acpi/actbl1.h @@ -79,9 +79,15 @@ #pragma pack(1) /* - * Note about bitfields: The u8 type is used for bitfields in ACPI tables. - * This is the only type that is even remotely portable. Anything else is not - * portable, so do not use any other bitfield types. + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 */ /******************************************************************************* diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h index b74476c0be8..1b2b356486d 100644 --- a/include/acpi/actbl2.h +++ b/include/acpi/actbl2.h @@ -98,9 +98,15 @@ #pragma pack(1) /* - * Note about bitfields: The u8 type is used for bitfields in ACPI tables. - * This is the only type that is even remotely portable. Anything else is not - * portable, so do not use any other bitfield types. + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 */ /******************************************************************************* diff --git a/include/acpi/actbl3.h b/include/acpi/actbl3.h index 37781ab806a..8c61b5fe42a 100644 --- a/include/acpi/actbl3.h +++ b/include/acpi/actbl3.h @@ -86,9 +86,15 @@ #pragma pack(1) /* - * Note about bitfields: The u8 type is used for bitfields in ACPI tables. - * This is the only type that is even remotely portable. Anything else is not - * portable, so do not use any other bitfield types. + * Note: C bitfields are not used for this reason: + * + * "Bitfields are great and easy to read, but unfortunately the C language + * does not specify the layout of bitfields in memory, which means they are + * essentially useless for dealing with packed data in on-disk formats or + * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me, + * this decision was a design error in C. Ritchie could have picked an order + * and stuck with it." Norman Ramsey. + * See http://stackoverflow.com/a/1053662/41661 */ /******************************************************************************* |