diff options
Diffstat (limited to 'Documentation')
33 files changed, 1134 insertions, 181 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 6434f0df012..6cd6daefaae 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -20,7 +20,7 @@ Description: lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] - base: func:= [BPRM_CHECK][FILE_MMAP][INODE_PERMISSION] + base: func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK] mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC] fsmagic:= hex value uid:= decimal value @@ -40,11 +40,11 @@ Description: measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC - measure func=INODE_PERM mask=MAY_READ uid=0 + measure func=FILE_CHECK mask=MAY_READ uid=0 The default policy measures all executables in bprm_check, all files mmapped executable in file_mmap, and all files - open for read by root in inode_permission. + open for read by root in do_filp_open. Examples of LSM specific definitions: @@ -54,8 +54,8 @@ Description: dont_measure obj_type=var_log_t dont_measure obj_type=auditd_log_t - measure subj_user=system_u func=INODE_PERM mask=MAY_READ - measure subj_role=system_r func=INODE_PERM mask=MAY_READ + measure subj_user=system_u func=FILE_CHECK mask=MAY_READ + measure subj_role=system_r func=FILE_CHECK mask=MAY_READ Smack: - measure subj_user=_ func=INODE_PERM mask=MAY_READ + measure subj_user=_ func=FILE_CHECK mask=MAY_READ diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power new file mode 100644 index 00000000000..6123c523bfd --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -0,0 +1,79 @@ +What: /sys/devices/.../power/ +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../power directory contains attributes + allowing the user space to check and modify some power + management related properties of given device. + +What: /sys/devices/.../power/wakeup +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../power/wakeup attribute allows the user + space to check if the device is enabled to wake up the system + from sleep states, such as the memory sleep state (suspend to + RAM) and hibernation (suspend to disk), and to enable or disable + it to do that as desired. + + Some devices support "wakeup" events, which are hardware signals + used to activate the system from a sleep state. Such devices + have one of the following two values for the sysfs power/wakeup + file: + + + "enabled\n" to issue the events; + + "disabled\n" not to do so; + + In that cases the user space can change the setting represented + by the contents of this file by writing either "enabled", or + "disabled" to it. + + For the devices that are not capable of generating system wakeup + events this file contains "\n". In that cases the user space + cannot modify the contents of this file and the device cannot be + enabled to wake up the system. + +What: /sys/devices/.../power/control +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../power/control attribute allows the user + space to control the run-time power management of the device. + + All devices have one of the following two values for the + power/control file: + + + "auto\n" to allow the device to be power managed at run time; + + "on\n" to prevent the device from being power managed; + + The default for all devices is "auto", which means that they may + be subject to automatic power management, depending on their + drivers. Changing this attribute to "on" prevents the driver + from power managing the device at run time. Doing that while + the device is suspended causes it to be woken up. + +What: /sys/devices/.../power/async +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../async attribute allows the user space to + enable or diasble the device's suspend and resume callbacks to + be executed asynchronously (ie. in separate threads, in parallel + with the main suspend/resume thread) during system-wide power + transitions (eg. suspend to RAM, hibernation). + + All devices have one of the following two values for the + power/async file: + + + "enabled\n" to permit the asynchronous suspend/resume; + + "disabled\n" to forbid it; + + The value of this attribute may be changed by writing either + "enabled", or "disabled" to it. + + It generally is unsafe to permit the asynchronous suspend/resume + of a device unless it is certain that all of the PM dependencies + of the device are known to the PM core. However, for some + devices this attribute is set to "enabled" by bus type code or + device drivers and in that cases it should be safe to leave the + default value. diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index dcff4d0623a..d6a801f45b4 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power @@ -101,3 +101,16 @@ Description: CAUTION: Using it will cause your machine's real-time (CMOS) clock to be set to a random invalid time after a resume. + +What: /sys/power/pm_async +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/power/pm_async file controls the switch allowing the + user space to enable or disable asynchronous suspend and resume + of devices. If enabled, this feature will cause some device + drivers' suspend and resume callbacks to be executed in parallel + with each other and with the main suspend thread. It is enabled + if this file contains "1", which is the default. It may be + disabled by writing "0" to this file, in which case all devices + will be suspended and resumed synchronously. diff --git a/Documentation/DocBook/v4l/io.xml b/Documentation/DocBook/v4l/io.xml index f92f24323b2..e870330cbf7 100644 --- a/Documentation/DocBook/v4l/io.xml +++ b/Documentation/DocBook/v4l/io.xml @@ -589,7 +589,8 @@ number of a video input as in &v4l2-input; field <entry></entry> <entry>A place holder for future extensions and custom (driver defined) buffer types -<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher.</entry> +<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher. Applications +should set this to 0.</entry> </row> </tbody> </tgroup> diff --git a/Documentation/DocBook/v4l/vidioc-qbuf.xml b/Documentation/DocBook/v4l/vidioc-qbuf.xml index 18708177815..b843bd7b389 100644 --- a/Documentation/DocBook/v4l/vidioc-qbuf.xml +++ b/Documentation/DocBook/v4l/vidioc-qbuf.xml @@ -54,12 +54,10 @@ to enqueue an empty (capturing) or filled (output) buffer in the driver's incoming queue. The semantics depend on the selected I/O method.</para> - <para>To enqueue a <link linkend="mmap">memory mapped</link> -buffer applications set the <structfield>type</structfield> field of a -&v4l2-buffer; to the same buffer type as previously &v4l2-format; -<structfield>type</structfield> and &v4l2-requestbuffers; -<structfield>type</structfield>, the <structfield>memory</structfield> -field to <constant>V4L2_MEMORY_MMAP</constant> and the + <para>To enqueue a buffer applications set the <structfield>type</structfield> +field of a &v4l2-buffer; to the same buffer type as was previously used +with &v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>. Applications must also set the <structfield>index</structfield> field. Valid index numbers range from zero to the number of buffers allocated with &VIDIOC-REQBUFS; (&v4l2-requestbuffers; <structfield>count</structfield>) minus one. The @@ -70,8 +68,19 @@ intended for output (<structfield>type</structfield> is <constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also initialize the <structfield>bytesused</structfield>, <structfield>field</structfield> and -<structfield>timestamp</structfield> fields. See <xref - linkend="buffer" /> for details. When +<structfield>timestamp</structfield> fields, see <xref +linkend="buffer" /> for details. +Applications must also set <structfield>flags</structfield> to 0. If a driver +supports capturing from specific video inputs and you want to specify a video +input, then <structfield>flags</structfield> should be set to +<constant>V4L2_BUF_FLAG_INPUT</constant> and the field +<structfield>input</structfield> must be initialized to the desired input. +The <structfield>reserved</structfield> field must be set to 0. +</para> + + <para>To enqueue a <link linkend="mmap">memory mapped</link> +buffer applications set the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_MMAP</constant>. When <constant>VIDIOC_QBUF</constant> is called with a pointer to this structure the driver sets the <constant>V4L2_BUF_FLAG_MAPPED</constant> and @@ -81,14 +90,10 @@ structure the driver sets the &EINVAL;.</para> <para>To enqueue a <link linkend="userp">user pointer</link> -buffer applications set the <structfield>type</structfield> field of a -&v4l2-buffer; to the same buffer type as previously &v4l2-format; -<structfield>type</structfield> and &v4l2-requestbuffers; -<structfield>type</structfield>, the <structfield>memory</structfield> -field to <constant>V4L2_MEMORY_USERPTR</constant> and the +buffer applications set the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_USERPTR</constant>, the <structfield>m.userptr</structfield> field to the address of the -buffer and <structfield>length</structfield> to its size. When the -buffer is intended for output additional fields must be set as above. +buffer and <structfield>length</structfield> to its size. When <constant>VIDIOC_QBUF</constant> is called with a pointer to this structure the driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant> flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and @@ -96,13 +101,14 @@ flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and <structfield>flags</structfield> field, or it returns an error code. This ioctl locks the memory pages of the buffer in physical memory, they cannot be swapped out to disk. Buffers remain locked until -dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl are +dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is called, or until the device is closed.</para> <para>Applications call the <constant>VIDIOC_DQBUF</constant> ioctl to dequeue a filled (capturing) or displayed (output) buffer from the driver's outgoing queue. They just set the -<structfield>type</structfield> and <structfield>memory</structfield> +<structfield>type</structfield>, <structfield>memory</structfield> +and <structfield>reserved</structfield> fields of a &v4l2-buffer; as above, when <constant>VIDIOC_DQBUF</constant> is called with a pointer to this structure the driver fills the remaining fields or returns an error code.</para> diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml index d834993e619..e649805a490 100644 --- a/Documentation/DocBook/v4l/vidioc-querybuf.xml +++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml @@ -54,12 +54,13 @@ buffer at any time after buffers have been allocated with the &VIDIOC-REQBUFS; ioctl.</para> <para>Applications set the <structfield>type</structfield> field - of a &v4l2-buffer; to the same buffer type as previously + of a &v4l2-buffer; to the same buffer type as was previously used with &v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; <structfield>type</structfield>, and the <structfield>index</structfield> field. Valid index numbers range from zero to the number of buffers allocated with &VIDIOC-REQBUFS; (&v4l2-requestbuffers; <structfield>count</structfield>) minus one. +The <structfield>reserved</structfield> field should to set to 0. After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to this structure drivers return an error code or fill the rest of the structure.</para> @@ -68,8 +69,8 @@ the structure.</para> <constant>V4L2_BUF_FLAG_MAPPED</constant>, <constant>V4L2_BUF_FLAG_QUEUED</constant> and <constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The -<structfield>memory</structfield> field will be set to -<constant>V4L2_MEMORY_MMAP</constant>, the <structfield>m.offset</structfield> +<structfield>memory</structfield> field will be set to the current +I/O method, the <structfield>m.offset</structfield> contains the offset of the buffer from the start of the device memory, the <structfield>length</structfield> field its size. The driver may or may not set the remaining fields and flags, they are meaningless in diff --git a/Documentation/DocBook/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/v4l/vidioc-reqbufs.xml index bab38084454..1c081637207 100644 --- a/Documentation/DocBook/v4l/vidioc-reqbufs.xml +++ b/Documentation/DocBook/v4l/vidioc-reqbufs.xml @@ -54,23 +54,23 @@ I/O. Memory mapped buffers are located in device memory and must be allocated with this ioctl before they can be mapped into the application's address space. User buffers are allocated by applications themselves, and this ioctl is merely used to switch the -driver into user pointer I/O mode.</para> +driver into user pointer I/O mode and to setup some internal structures.</para> - <para>To allocate device buffers applications initialize three -fields of a <structname>v4l2_requestbuffers</structname> structure. + <para>To allocate device buffers applications initialize all +fields of the <structname>v4l2_requestbuffers</structname> structure. They set the <structfield>type</structfield> field to the respective stream or buffer type, the <structfield>count</structfield> field to -the desired number of buffers, and <structfield>memory</structfield> -must be set to <constant>V4L2_MEMORY_MMAP</constant>. When the ioctl -is called with a pointer to this structure the driver attempts to -allocate the requested number of buffers and stores the actual number +the desired number of buffers, <structfield>memory</structfield> +must be set to the requested I/O method and the reserved array +must be zeroed. When the ioctl +is called with a pointer to this structure the driver will attempt to allocate +the requested number of buffers and it stores the actual number allocated in the <structfield>count</structfield> field. It can be smaller than the number requested, even zero, when the driver runs out -of free memory. A larger number is possible when the driver requires -more buffers to function correctly.<footnote> - <para>For example video output requires at least two buffers, +of free memory. A larger number is also possible when the driver requires +more buffers to function correctly. For example video output requires at least two buffers, one displayed and one filled by the application.</para> - </footnote> When memory mapping I/O is not supported the ioctl + <para>When the I/O method is not supported the ioctl returns an &EINVAL;.</para> <para>Applications can call <constant>VIDIOC_REQBUFS</constant> @@ -81,14 +81,6 @@ in progress, an implicit &VIDIOC-STREAMOFF;. <!-- mhs: I see no reason why munmap()ping one or even all buffers must imply streamoff.--></para> - <para>To negotiate user pointer I/O, applications initialize only -the <structfield>type</structfield> field and set -<structfield>memory</structfield> to -<constant>V4L2_MEMORY_USERPTR</constant>. When the ioctl is called -with a pointer to this structure the driver prepares for user pointer -I/O, when this I/O method is not supported the ioctl returns an -&EINVAL;.</para> - <table pgwide="1" frame="none" id="v4l2-requestbuffers"> <title>struct <structname>v4l2_requestbuffers</structname></title> <tgroup cols="3"> @@ -97,9 +89,7 @@ I/O, when this I/O method is not supported the ioctl returns an <row> <entry>__u32</entry> <entry><structfield>count</structfield></entry> - <entry>The number of buffers requested or granted. This -field is only used when <structfield>memory</structfield> is set to -<constant>V4L2_MEMORY_MMAP</constant>.</entry> + <entry>The number of buffers requested or granted.</entry> </row> <row> <entry>&v4l2-buf-type;</entry> @@ -120,7 +110,7 @@ as the &v4l2-format; <structfield>type</structfield> field. See <xref <entry><structfield>reserved</structfield>[2]</entry> <entry>A place holder for future extensions and custom (driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and -higher.</entry> +higher. This array should be zeroed by applications.</entry> </row> </tbody> </tgroup> diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt index da42ab414c4..b231414bb8b 100644 --- a/Documentation/cachetlb.txt +++ b/Documentation/cachetlb.txt @@ -377,3 +377,27 @@ maps this page at its virtual address. All the functionality of flush_icache_page can be implemented in flush_dcache_page and update_mmu_cache. In 2.7 the hope is to remove this interface completely. + +The final category of APIs is for I/O to deliberately aliased address +ranges inside the kernel. Such aliases are set up by use of the +vmap/vmalloc API. Since kernel I/O goes via physical pages, the I/O +subsystem assumes that the user mapping and kernel offset mapping are +the only aliases. This isn't true for vmap aliases, so anything in +the kernel trying to do I/O to vmap areas must manually manage +coherency. It must do this by flushing the vmap range before doing +I/O and invalidating it after the I/O returns. + + void flush_kernel_vmap_range(void *vaddr, int size) + flushes the kernel cache for a given virtual address range in + the vmap area. This is to make sure that any data the kernel + modified in the vmap range is made visible to the physical + page. The design is to make this area safe to perform I/O on. + Note that this API does *not* also flush the offset map alias + of the area. + + void invalidate_kernel_vmap_range(void *vaddr, int size) invalidates + the cache for a given virtual address range in the vmap area + which prevents the processor from making the cache stale by + speculatively reading data while the I/O was occurring to the + physical pages. This is only necessary for data reads into the + vmap area. diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt index aed082f49d0..737988fca64 100644 --- a/Documentation/cpu-freq/governors.txt +++ b/Documentation/cpu-freq/governors.txt @@ -145,8 +145,8 @@ show_sampling_rate_max: THIS INTERFACE IS DEPRECATED, DON'T USE IT. up_threshold: defines what the average CPU usage between the samplings of 'sampling_rate' needs to be for the kernel to make a decision on whether it should increase the frequency. For example when it is set -to its default value of '80' it means that between the checking -intervals the CPU needs to be on average more than 80% in use to then +to its default value of '95' it means that between the checking +intervals the CPU needs to be on average more than 95% in use to then decide that the CPU frequency needs to be increased. ignore_nice_load: this parameter takes a value of '0' or '1'. When diff --git a/Documentation/dontdiff b/Documentation/dontdiff index 3ad6acead94..d9bcffd5943 100644 --- a/Documentation/dontdiff +++ b/Documentation/dontdiff @@ -69,7 +69,6 @@ av_permissions.h bbootsect bin2c binkernel.spec -binoffset bootsect bounds.h bsetup diff --git a/Documentation/dvb/get_dvb_firmware b/Documentation/dvb/get_dvb_firmware index 14b7b5a3bcb..239cbdbf4d1 100644 --- a/Documentation/dvb/get_dvb_firmware +++ b/Documentation/dvb/get_dvb_firmware @@ -26,7 +26,7 @@ use IO::Handle; "dec3000s", "vp7041", "dibusb", "nxt2002", "nxt2004", "or51211", "or51132_qam", "or51132_vsb", "bluebird", "opera1", "cx231xx", "cx18", "cx23885", "pvrusb2", "mpc718", - "af9015"); + "af9015", "ngene"); # Check args syntax() if (scalar(@ARGV) != 1); @@ -39,7 +39,7 @@ for ($i=0; $i < scalar(@components); $i++) { die $@ if $@; print STDERR <<EOF; Firmware(s) $outfile extracted successfully. -Now copy it(they) to either /usr/lib/hotplug/firmware or /lib/firmware +Now copy it(them) to either /usr/lib/hotplug/firmware or /lib/firmware (depending on configuration of firmware hotplug). EOF exit(0); @@ -549,6 +549,24 @@ sub af9015 { close INFILE; } +sub ngene { + my $url = "http://www.digitaldevices.de/download/"; + my $file1 = "ngene_15.fw"; + my $hash1 = "d798d5a757121174f0dbc5f2833c0c85"; + my $file2 = "ngene_17.fw"; + my $hash2 = "26b687136e127b8ac24b81e0eeafc20b"; + + checkstandard(); + + wgetfile($file1, $url . $file1); + verify($file1, $hash1); + + wgetfile($file2, $url . $file2); + verify($file2, $hash2); + + "$file1, $file2"; +} + # --------------------------------------------------------------- # Utilities @@ -667,6 +685,7 @@ sub delzero{ sub syntax() { print STDERR "syntax: get_dvb_firmware <component>\n"; print STDERR "Supported components:\n"; + @components = sort @components; for($i=0; $i < scalar(@components); $i++) { print STDERR "\t" . $components[$i] . "\n"; } diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index 07930564079..7be15e44d48 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -143,8 +143,8 @@ o provide a way to configure fault attributes failslab, fail_page_alloc, and fail_make_request use this way. Helper functions: - init_fault_attr_entries(entries, attr, name); - void cleanup_fault_attr_entries(entries); + init_fault_attr_dentries(entries, attr, name); + void cleanup_fault_attr_dentries(entries); - module parameters diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 870d190fe61..b9eba900e0f 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -64,6 +64,17 @@ Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com> --------------------------- +What: Deprecated snapshot ioctls +When: 2.6.36 + +Why: The ioctls in kernel/power/user.c were marked as deprecated long time + ago. Now they notify users about that so that they need to replace + their userspace. After some more time, remove them completely. + +Who: Jiri Slaby <jirislaby@gmail.com> + +--------------------------- + What: The ieee80211_regdom module parameter When: March 2010 / desktop catchup @@ -493,3 +504,52 @@ Why: These two features use non-standard interfaces. There are the Who: Corentin Chary <corentin.chary@gmail.com> ---------------------------- + +What: usbvideo quickcam_messenger driver +When: 2.6.35 +Files: drivers/media/video/usbvideo/quickcam_messenger.[ch] +Why: obsolete v4l1 driver replaced by gspca_stv06xx +Who: Hans de Goede <hdegoede@redhat.com> + +---------------------------- + +What: ov511 v4l1 driver +When: 2.6.35 +Files: drivers/media/video/ov511.[ch] +Why: obsolete v4l1 driver replaced by gspca_ov519 +Who: Hans de Goede <hdegoede@redhat.com> + +---------------------------- + +What: w9968cf v4l1 driver +When: 2.6.35 +Files: drivers/media/video/w9968cf*.[ch] +Why: obsolete v4l1 driver replaced by gspca_ov519 +Who: Hans de Goede <hdegoede@redhat.com> + +---------------------------- + +What: ovcamchip sensor framework +When: 2.6.35 +Files: drivers/media/video/ovcamchip/* +Why: Only used by obsoleted v4l1 drivers +Who: Hans de Goede <hdegoede@redhat.com> + +---------------------------- + +What: stv680 v4l1 driver +When: 2.6.35 +Files: drivers/media/video/stv680.[ch] +Why: obsolete v4l1 driver replaced by gspca_stv0680 +Who: Hans de Goede <hdegoede@redhat.com> + +---------------------------- + +What: zc0301 v4l driver +When: 2.6.35 +Files: drivers/media/video/zc0301/* +Why: Duplicate functionality with the gspca_zc3xx driver, zc0301 only + supports 2 USB-ID's (because it only supports a limited set of + sensors) wich are also supported by the gspca_zc3xx driver + (which supports 53 USB-ID's in total) +Who: Hans de Goede <hdegoede@redhat.com> diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt index a12ea3b586e..8490480ce43 100644 --- a/Documentation/input/multi-touch-protocol.txt +++ b/Documentation/input/multi-touch-protocol.txt @@ -27,12 +27,30 @@ set of events/packets. A set of ABS_MT events with the desired properties is defined. The events are divided into categories, to allow for partial implementation. The -minimum set consists of ABS_MT_TOUCH_MAJOR, ABS_MT_POSITION_X and -ABS_MT_POSITION_Y, which allows for multiple fingers to be tracked. If the -device supports it, the ABS_MT_WIDTH_MAJOR may be used to provide the size -of the approaching finger. Anisotropy and direction may be specified with -ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and ABS_MT_ORIENTATION. The -ABS_MT_TOOL_TYPE may be used to specify whether the touching tool is a +minimum set consists of ABS_MT_POSITION_X and ABS_MT_POSITION_Y, which +allows for multiple fingers to be tracked. If the device supports it, the +ABS_MT_TOUCH_MAJOR and ABS_MT_WIDTH_MAJOR may be used to provide the size +of the contact area and approaching finger, respectively. + +The TOUCH and WIDTH parameters have a geometrical interpretation; imagine +looking through a window at someone gently holding a finger against the +glass. You will see two regions, one inner region consisting of the part +of the finger actually touching the glass, and one outer region formed by +the perimeter of the finger. The diameter of the inner region is the +ABS_MT_TOUCH_MAJOR, the diameter of the outer region is +ABS_MT_WIDTH_MAJOR. Now imagine the person pressing the finger harder +against the glass. The inner region will increase, and in general, the +ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR, which is always smaller than +unity, is related to the finger pressure. For pressure-based devices, +ABS_MT_PRESSURE may be used to provide the pressure on the contact area +instead. + +In addition to the MAJOR parameters, the oval shape of the finger can be +described by adding the MINOR parameters, such that MAJOR and MINOR are the +major and minor axis of an ellipse. Finally, the orientation of the oval +shape can be describe with the ORIENTATION parameter. + +The ABS_MT_TOOL_TYPE may be used to specify whether the touching tool is a finger or a pen or something else. Devices with more granular information may specify general shapes as blobs, i.e., as a sequence of rectangular shapes grouped togethe |