<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/hid, branch linux-3.14.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>HID: hid-input: Add parentheses to quell gcc warning</title>
<updated>2016-09-11T07:59:58+00:00</updated>
<author>
<name>James C Boyd</name>
<email>jcboyd.dev@gmail.com</email>
</author>
<published>2015-05-27T22:09:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ac98961e44fa5df4383f0a60f0c4923f368da1d8'/>
<id>ac98961e44fa5df4383f0a60f0c4923f368da1d8</id>
<content type='text'>
commit 09a5c34e8d6b05663ec4c3d22b1fbd9fec89aaf9 upstream.

GCC reports a -Wlogical-not-parentheses warning here; therefore
add parentheses to shut it up and to express our intent more.

Signed-off-by: James C Boyd &lt;jcboyd.dev@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Cc: Willy Tarreau &lt;w@1wt.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 09a5c34e8d6b05663ec4c3d22b1fbd9fec89aaf9 upstream.

GCC reports a -Wlogical-not-parentheses warning here; therefore
add parentheses to shut it up and to express our intent more.

Signed-off-by: James C Boyd &lt;jcboyd.dev@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Cc: Willy Tarreau &lt;w@1wt.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands</title>
<updated>2016-07-27T16:55:50+00:00</updated>
<author>
<name>Scott Bauer</name>
<email>sbauer@plzdonthack.me</email>
</author>
<published>2016-06-23T14:59:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=22e658d19a1a64512d49de2632ad2124e6f9e429'/>
<id>22e658d19a1a64512d49de2632ad2124e6f9e429</id>
<content type='text'>
commit 93a2001bdfd5376c3dc2158653034c20392d15c5 upstream.

This patch validates the num_values parameter from userland during the
HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
leading to a heap overflow.

Signed-off-by: Scott Bauer &lt;sbauer@plzdonthack.me&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 93a2001bdfd5376c3dc2158653034c20392d15c5 upstream.

This patch validates the num_values parameter from userland during the
HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
leading to a heap overflow.

Signed-off-by: Scott Bauer &lt;sbauer@plzdonthack.me&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: elo: kill not flush the work</title>
<updated>2016-07-27T16:55:50+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2016-05-31T12:48:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=48650aa9bba3a8c0d917b172753330c2f7f8a99a'/>
<id>48650aa9bba3a8c0d917b172753330c2f7f8a99a</id>
<content type='text'>
commit ed596a4a88bd161f868ccba078557ee7ede8a6ef upstream.

Flushing a work that reschedules itself is not a sensible operation. It needs
to be killed. Failure to do so leads to a kernel panic in the timer code.

Signed-off-by: Oliver Neukum &lt;ONeukum@suse.com&gt;
Reviewed-by: Benjamin Tissoires &lt;benjamin.tissoires@redhat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ed596a4a88bd161f868ccba078557ee7ede8a6ef upstream.

Flushing a work that reschedules itself is not a sensible operation. It needs
to be killed. Failure to do so leads to a kernel panic in the timer code.

Signed-off-by: Oliver Neukum &lt;ONeukum@suse.com&gt;
Reviewed-by: Benjamin Tissoires &lt;benjamin.tissoires@redhat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: usbhid: fix inconsistent reset/resume/reset-resume behavior</title>
<updated>2016-04-20T06:40:45+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2016-03-23T16:17:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0caa9766ca3ad03680a539b5023163a36702728d'/>
<id>0caa9766ca3ad03680a539b5023163a36702728d</id>
<content type='text'>
commit 972e6a993f278b416a8ee3ec65475724fc36feb2 upstream.

The usbhid driver has inconsistently duplicated code in its post-reset,
resume, and reset-resume pathways.

	reset-resume doesn't check HID_STARTED before trying to
	restart the I/O queues.

	resume fails to clear the HID_SUSPENDED flag if HID_STARTED
	isn't set.

	resume calls usbhid_restart_queues() with usbhid-&gt;lock held
	and the others call it without holding the lock.

The first item in particular causes a problem following a reset-resume
if the driver hasn't started up its I/O.  URB submission fails because
usbhid-&gt;urbin is NULL, and this triggers an unending reset-retry loop.

This patch fixes the problem by creating a new subroutine,
hid_restart_io(), to carry out all the common activities.  It also
adds some checks that were missing in the original code:

	After a reset, there's no need to clear any halted endpoints.

	After a resume, if a reset is pending there's no need to
	restart any I/O until the reset is finished.

	After a resume, if the interrupt-IN endpoint is halted there's
	no need to submit the input URB until the halt has been
	cleared.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Daniel Fraga &lt;fragabr@gmail.com&gt;
Tested-by: Daniel Fraga &lt;fragabr@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 972e6a993f278b416a8ee3ec65475724fc36feb2 upstream.

The usbhid driver has inconsistently duplicated code in its post-reset,
resume, and reset-resume pathways.

	reset-resume doesn't check HID_STARTED before trying to
	restart the I/O queues.

	resume fails to clear the HID_SUSPENDED flag if HID_STARTED
	isn't set.

	resume calls usbhid_restart_queues() with usbhid-&gt;lock held
	and the others call it without holding the lock.

The first item in particular causes a problem following a reset-resume
if the driver hasn't started up its I/O.  URB submission fails because
usbhid-&gt;urbin is NULL, and this triggers an unending reset-retry loop.

This patch fixes the problem by creating a new subroutine,
hid_restart_io(), to carry out all the common activities.  It also
adds some checks that were missing in the original code:

	After a reset, there's no need to clear any halted endpoints.

	After a resume, if a reset is pending there's no need to
	restart any I/O until the reset is finished.

	After a resume, if the interrupt-IN endpoint is halted there's
	no need to submit the input URB until the halt has been
	cleared.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Daniel Fraga &lt;fragabr@gmail.com&gt;
Tested-by: Daniel Fraga &lt;fragabr@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: logitech: fix Dual Action gamepad support</title>
<updated>2016-04-12T16:12:44+00:00</updated>
<author>
<name>Grazvydas Ignotas</name>
<email>notasas@gmail.com</email>
</author>
<published>2016-02-13T20:41:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cc4033eb848c13ac568e8d2bea7e5be960d85ca2'/>
<id>cc4033eb848c13ac568e8d2bea7e5be960d85ca2</id>
<content type='text'>
commit 5d74325a2201376a95520a4a38a1ce2c65761c49 upstream.

The patch that added Logitech Dual Action gamepad support forgot to
update the special driver list for the device. This caused the logitech
driver not to probe unless kernel module load order was favorable.
Update the special driver list to fix it. Thanks to Simon Wood for the
idea.

Cc: Vitaly Katraew &lt;zawullon@gmail.com&gt;
Fixes: 56d0c8b7c8fb ("HID: add support for Logitech Dual Action gamepads")
Signed-off-by: Grazvydas Ignotas &lt;notasas@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5d74325a2201376a95520a4a38a1ce2c65761c49 upstream.

The patch that added Logitech Dual Action gamepad support forgot to
update the special driver list for the device. This caused the logitech
driver not to probe unless kernel module load order was favorable.
Update the special driver list to fix it. Thanks to Simon Wood for the
idea.

Cc: Vitaly Katraew &lt;zawullon@gmail.com&gt;
Fixes: 56d0c8b7c8fb ("HID: add support for Logitech Dual Action gamepads")
Signed-off-by: Grazvydas Ignotas &lt;notasas@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: usbhid: fix recursive deadlock</title>
<updated>2016-02-17T20:34:34+00:00</updated>
<author>
<name>Ioan-Adrian Ratiu</name>
<email>adi@adirat.com</email>
</author>
<published>2015-11-20T20:19:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fcb65392c93b27fbc302eccc42e0e2824df7e1d5'/>
<id>fcb65392c93b27fbc302eccc42e0e2824df7e1d5</id>
<content type='text'>
commit e470127e9606b1fa151c4184243e61296d1e0c0f upstream.

The critical section protected by usbhid-&gt;lock in hid_ctrl() is too
big and because of this it causes a recursive deadlock. "Too big" means
the case statement and the call to hid_input_report() do not need to be
protected by the spinlock (no URB operations are done inside them).

The deadlock happens because in certain rare cases drivers try to grab
the lock while handling the ctrl irq which grabs the lock before them
as described above. For example newer wacom tablets like 056a:033c try
to reschedule proximity reads from wacom_intuos_schedule_prox_event()
calling hid_hw_request() -&gt; usbhid_request() -&gt; usbhid_submit_report()
which tries to grab the usbhid lock already held by hid_ctrl().

There are two ways to get out of this deadlock:
    1. Make the drivers work "around" the ctrl critical region, in the
    wacom case for ex. by delaying the scheduling of the proximity read
    request itself to a workqueue.
    2. Shrink the critical region so the usbhid lock protects only the
    instructions which modify usbhid state, calling hid_input_report()
    with the spinlock unlocked, allowing the device driver to grab the
    lock first, finish and then grab the lock afterwards in hid_ctrl().

This patch implements the 2nd solution.

Signed-off-by: Ioan-Adrian Ratiu &lt;adi@adirat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Jason Gerecke &lt;jason.gerecke@wacom.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e470127e9606b1fa151c4184243e61296d1e0c0f upstream.

The critical section protected by usbhid-&gt;lock in hid_ctrl() is too
big and because of this it causes a recursive deadlock. "Too big" means
the case statement and the call to hid_input_report() do not need to be
protected by the spinlock (no URB operations are done inside them).

The deadlock happens because in certain rare cases drivers try to grab
the lock while handling the ctrl irq which grabs the lock before them
as described above. For example newer wacom tablets like 056a:033c try
to reschedule proximity reads from wacom_intuos_schedule_prox_event()
calling hid_hw_request() -&gt; usbhid_request() -&gt; usbhid_submit_report()
which tries to grab the usbhid lock already held by hid_ctrl().

There are two ways to get out of this deadlock:
    1. Make the drivers work "around" the ctrl critical region, in the
    wacom case for ex. by delaying the scheduling of the proximity read
    request itself to a workqueue.
    2. Shrink the critical region so the usbhid lock protects only the
    instructions which modify usbhid state, calling hid_input_report()
    with the spinlock unlocked, allowing the device driver to grab the
    lock first, finish and then grab the lock afterwards in hid_ctrl().

This patch implements the 2nd solution.

Signed-off-by: Ioan-Adrian Ratiu &lt;adi@adirat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Jason Gerecke &lt;jason.gerecke@wacom.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: core: Avoid uninitialized buffer access</title>
<updated>2016-01-29T05:57:15+00:00</updated>
<author>
<name>Richard Purdie</name>
<email>richard.purdie@linuxfoundation.org</email>
</author>
<published>2015-09-18T23:31:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=389642cf5e593a059433444ef694c95510f4bfe9'/>
<id>389642cf5e593a059433444ef694c95510f4bfe9</id>
<content type='text'>
commit 79b568b9d0c7c5d81932f4486d50b38efdd6da6d upstream.

hid_connect adds various strings to the buffer but they're all
conditional. You can find circumstances where nothing would be written
to it but the kernel will still print the supposedly empty buffer with
printk. This leads to corruption on the console/in the logs.

Ensure buf is initialized to an empty string.

Signed-off-by: Richard Purdie &lt;richard.purdie@linuxfoundation.org&gt;
[dvhart: Initialize string to "" rather than assign buf[0] = NULL;]
Cc: Jiri Kosina &lt;jikos@kernel.org&gt;
Cc: linux-input@vger.kernel.org
Signed-off-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 79b568b9d0c7c5d81932f4486d50b38efdd6da6d upstream.

hid_connect adds various strings to the buffer but they're all
conditional. You can find circumstances where nothing would be written
to it but the kernel will still print the supposedly empty buffer with
printk. This leads to corruption on the console/in the logs.

Ensure buf is initialized to an empty string.

Signed-off-by: Richard Purdie &lt;richard.purdie@linuxfoundation.org&gt;
[dvhart: Initialize string to "" rather than assign buf[0] = NULL;]
Cc: Jiri Kosina &lt;jikos@kernel.org&gt;
Cc: linux-input@vger.kernel.org
Signed-off-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: usbhid: Fix the check for HID_RESET_PENDING in hid_io_error</title>
<updated>2015-09-21T17:02:19+00:00</updated>
<author>
<name>Don Zickus</name>
<email>dzickus@redhat.com</email>
</author>
<published>2015-08-10T16:06:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0f180c2bb4272aa60693262ec15b5a41443a0b2d'/>
<id>0f180c2bb4272aa60693262ec15b5a41443a0b2d</id>
<content type='text'>
commit 3af4e5a95184d6d3c1c6a065f163faa174a96a1d upstream.

It was reported that after 10-20 reboots, a usb keyboard plugged
into a docking station would not work unless it was replugged in.

Using usbmon, it turns out the interrupt URBs were streaming with
callback errors of -71 for some reason.  The hid-core.c::hid_io_error was
supposed to retry and then reset, but the reset wasn't really happening.

The check for HID_NO_BANDWIDTH was inverted.  Fix was simple.

Tested by reporter and locally by me by unplugging a keyboard halfway until I
could recreate a stream of errors but no disconnect.

Signed-off-by: Don Zickus &lt;dzickus@redhat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3af4e5a95184d6d3c1c6a065f163faa174a96a1d upstream.

It was reported that after 10-20 reboots, a usb keyboard plugged
into a docking station would not work unless it was replugged in.

Using usbmon, it turns out the interrupt URBs were streaming with
callback errors of -71 for some reason.  The hid-core.c::hid_io_error was
supposed to retry and then reset, but the reset wasn't really happening.

The check for HID_NO_BANDWIDTH was inverted.  Fix was simple.

Tested by reporter and locally by me by unplugging a keyboard halfway until I
could recreate a stream of errors but no disconnect.

Signed-off-by: Don Zickus &lt;dzickus@redhat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: fixup the conflicting keyboard mappings quirk</title>
<updated>2015-03-18T12:31:33+00:00</updated>
<author>
<name>Jiri Kosina</name>
<email>jkosina@suse.cz</email>
</author>
<published>2015-01-06T21:34:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f3995eb51ca8cab80105fb01f128f10839298145'/>
<id>f3995eb51ca8cab80105fb01f128f10839298145</id>
<content type='text'>
commit 8e7b341037db1835ee6eea64663013cbfcf33575 upstream.

The ignore check that got added in 6ce901eb61 ("HID: input: fix confusion
on conflicting mappings") needs to properly check for VARIABLE reports
as well (ARRAY reports should be ignored), otherwise legitimate keyboards
might break.

Fixes: 6ce901eb61 ("HID: input: fix confusion on conflicting mappings")
Reported-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Reported-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8e7b341037db1835ee6eea64663013cbfcf33575 upstream.

The ignore check that got added in 6ce901eb61 ("HID: input: fix confusion
on conflicting mappings") needs to properly check for VARIABLE reports
as well (ARRAY reports should be ignored), otherwise legitimate keyboards
might break.

Fixes: 6ce901eb61 ("HID: input: fix confusion on conflicting mappings")
Reported-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Reported-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>HID: input: fix confusion on conflicting mappings</title>
<updated>2015-03-18T12:31:33+00:00</updated>
<author>
<name>David Herrmann</name>
<email>dh.herrmann@gmail.com</email>
</author>
<published>2014-12-29T14:21:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=20f6cd730adc80de1368290df4db9195a96e5ad6'/>
<id>20f6cd730adc80de1368290df4db9195a96e5ad6</id>
<content type='text'>
commit 6ce901eb61aa30ba8565c62049ee80c90728ef14 upstream.

On an PC-101/103/104 keyboard (American layout) the 'Enter' key and its
neighbours look like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |   5   |
           +---+ +---+ +-------+
             +---+ +-----------+
             | 3 | |     4     |
             +---+ +-----------+

On a PC-102/105 keyboard (European layout) it looks like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |       |
           +---+ +---+ +-+  4  |
             +---+ +---+ |     |
             | 3 | | 5 | |     |
             +---+ +---+ +-----+

(Note that the number of keys is the same, but key '5' is moved down and
 the shape of key '4' is changed. Keys '1' to '3' are exactly the same.)

The keys 1-4 report the same scan-code in HID in both layouts, even though
the keysym they produce is usually different depending on the XKB-keymap
used by user-space.
However, key '5' (US 'backslash'/'pipe') reports 0x31 for the upper layout
and 0x32 for the lower layout, as defined by the HID spec. This is highly
confusing as the linux-input API uses a single keycode for both.

So far, this was never a problem as there never has been a keyboard with
both of those keys present at the same time. It would have to look
something like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |  x31  |
           +---+ +---+ +-------+
             +---+ +---+ +-----+
             | 3 | |x32| |  4  |
             +---+ +---+ +-----+

HID can represent such a keyboard, but the linux-input API cannot.
Furthermore, any user-space mapping would be confused by this and,
luckily, no-one ever produced such hardware.

Now, the HID input layer fixed this mess by mapping both 0x31 and 0x32 to
the same keycode (KEY_BACKSLASH==0x2b). As only one of both physical keys
is present on a hardware, this works just fine.

Lets introduce hardware-vendors into this:
------------------------------------------

Unfortunately, it seems way to expensive to produce a different device for
American and European layouts. Therefore, hardware-vendors put both keys,
(0x31 and 0x32) on the same keyboard, but only one of them is hooked up
to the physical button, the other one is 'dead'.
This means, they can use the same hardware, with a different button-layout
and automatically produce the correct HID events for American *and*
European layouts. This is unproblematic for normal keyboards, as the
'dead' key will never report any KEY-DOWN events. But RollOver keyboards
send the whole matrix on each key-event, allowing n-key roll-over mode.
This means, we get a 0x31 and 0x32 event on each key-press. One of them
will always be 0, the other reports the real state. As we map both to the
same keycode, we will get spurious key-events, even though the real
key-state never changed.

The easiest way would be to blacklist 'dead' keys and never handle those.
We could simply read the 'country' tag of USB devices and blacklist either
key according to the layout. But... hardware vendors... want the same
device for all countries and thus many of them set 'country' to 0 for all
devices. Meh..

So we have to deal with this properly. As we cannot know which of the keys
is 'dead', we either need a heuristic and track those keys, or we simply
make use of our value-tracking for HID fields. We simply ignore HID events
for absolute data if the data didn't change. As HID tracks events on the
HID level, we haven't done the keycode translation, yet. Therefore, the
'dead' key is tracked independently of the real key, therefore, any events
on it will be ignored.

This patch simply discards any HID events for absolute data if it didn't
change compared to the last report. We need to ignore relative and
buffered-byte reports for obvious reasons. But those cannot be affected by
this bug, so we're fine.

Preferably, we'd do this filtering on the HID-core level. But this might
break a lot of custom drivers, if they do not follow the HID specs.
Therefore, we do this late in hid-input just before we inject it into the
input layer (which does the exact same filtering, but on the keycode
level).

If this turns out to break some devices, we might have to limit filtering
to EV_KEY events. But lets try to do the Right Thing first, and properly
filter any absolute data that didn't change.

This patch is tagged for 'stable' as it fixes a lot of n-key RollOver
hardware. We might wanna wait with backporting for a while, before we know
it doesn't break anything else, though.

Reported-by: Adam Goode &lt;adam@spicenitz.org&gt;
Reported-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Tested-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Signed-off-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6ce901eb61aa30ba8565c62049ee80c90728ef14 upstream.

On an PC-101/103/104 keyboard (American layout) the 'Enter' key and its
neighbours look like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |   5   |
           +---+ +---+ +-------+
             +---+ +-----------+
             | 3 | |     4     |
             +---+ +-----------+

On a PC-102/105 keyboard (European layout) it looks like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |       |
           +---+ +---+ +-+  4  |
             +---+ +---+ |     |
             | 3 | | 5 | |     |
             +---+ +---+ +-----+

(Note that the number of keys is the same, but key '5' is moved down and
 the shape of key '4' is changed. Keys '1' to '3' are exactly the same.)

The keys 1-4 report the same scan-code in HID in both layouts, even though
the keysym they produce is usually different depending on the XKB-keymap
used by user-space.
However, key '5' (US 'backslash'/'pipe') reports 0x31 for the upper layout
and 0x32 for the lower layout, as defined by the HID spec. This is highly
confusing as the linux-input API uses a single keycode for both.

So far, this was never a problem as there never has been a keyboard with
both of those keys present at the same time. It would have to look
something like this:

           +---+ +---+ +-------+
           | 1 | | 2 | |  x31  |
           +---+ +---+ +-------+
             +---+ +---+ +-----+
             | 3 | |x32| |  4  |
             +---+ +---+ +-----+

HID can represent such a keyboard, but the linux-input API cannot.
Furthermore, any user-space mapping would be confused by this and,
luckily, no-one ever produced such hardware.

Now, the HID input layer fixed this mess by mapping both 0x31 and 0x32 to
the same keycode (KEY_BACKSLASH==0x2b). As only one of both physical keys
is present on a hardware, this works just fine.

Lets introduce hardware-vendors into this:
------------------------------------------

Unfortunately, it seems way to expensive to produce a different device for
American and European layouts. Therefore, hardware-vendors put both keys,
(0x31 and 0x32) on the same keyboard, but only one of them is hooked up
to the physical button, the other one is 'dead'.
This means, they can use the same hardware, with a different button-layout
and automatically produce the correct HID events for American *and*
European layouts. This is unproblematic for normal keyboards, as the
'dead' key will never report any KEY-DOWN events. But RollOver keyboards
send the whole matrix on each key-event, allowing n-key roll-over mode.
This means, we get a 0x31 and 0x32 event on each key-press. One of them
will always be 0, the other reports the real state. As we map both to the
same keycode, we will get spurious key-events, even though the real
key-state never changed.

The easiest way would be to blacklist 'dead' keys and never handle those.
We could simply read the 'country' tag of USB devices and blacklist either
key according to the layout. But... hardware vendors... want the same
device for all countries and thus many of them set 'country' to 0 for all
devices. Meh..

So we have to deal with this properly. As we cannot know which of the keys
is 'dead', we either need a heuristic and track those keys, or we simply
make use of our value-tracking for HID fields. We simply ignore HID events
for absolute data if the data didn't change. As HID tracks events on the
HID level, we haven't done the keycode translation, yet. Therefore, the
'dead' key is tracked independently of the real key, therefore, any events
on it will be ignored.

This patch simply discards any HID events for absolute data if it didn't
change compared to the last report. We need to ignore relative and
buffered-byte reports for obvious reasons. But those cannot be affected by
this bug, so we're fine.

Preferably, we'd do this filtering on the HID-core level. But this might
break a lot of custom drivers, if they do not follow the HID specs.
Therefore, we do this late in hid-input just before we inject it into the
input layer (which does the exact same filtering, but on the keycode
level).

If this turns out to break some devices, we might have to limit filtering
to EV_KEY events. But lets try to do the Right Thing first, and properly
filter any absolute data that didn't change.

This patch is tagged for 'stable' as it fixes a lot of n-key RollOver
hardware. We might wanna wait with backporting for a while, before we know
it doesn't break anything else, though.

Reported-by: Adam Goode &lt;adam@spicenitz.org&gt;
Reported-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Tested-by: Fredrik Hallenberg &lt;megahallon@gmail.com&gt;
Signed-off-by: David Herrmann &lt;dh.herrmann@gmail.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
