<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/acpi, branch v3.4.100</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>ACPI / battery: Retry to get battery information if failed during probing</title>
<updated>2014-07-17T22:39:50+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2014-07-07T07:47:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cd0c28d2281c65aa0ae89be80abcbf8e21c885b4'/>
<id>cd0c28d2281c65aa0ae89be80abcbf8e21c885b4</id>
<content type='text'>
commit 75646e758a0ecbed5024454507d5be5b9ea9dcbf upstream.

Some machines (eg. Lenovo Z480) ECs are not stable during boot up
and causes battery driver fails to be loaded due to failure of getting
battery information from EC sometimes. After several retries, the
operation will work. This patch is to retry to get battery information 5
times if the first try fails.

[ backport to 3.14.5: removed second parameter in acpi_battery_update(),
introduced by the commit 9e50bc14a7f58b5d8a55973b2d69355852ae2dae (ACPI /
battery: Accelerate battery resume callback)]

[naszar &lt;naszar@ya.ru&gt;: backport to 3.14.5]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=75581
Reported-and-tested-by: naszar &lt;naszar@ya.ru&gt;
Cc: All applicable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 75646e758a0ecbed5024454507d5be5b9ea9dcbf upstream.

Some machines (eg. Lenovo Z480) ECs are not stable during boot up
and causes battery driver fails to be loaded due to failure of getting
battery information from EC sometimes. After several retries, the
operation will work. This patch is to retry to get battery information 5
times if the first try fails.

[ backport to 3.14.5: removed second parameter in acpi_battery_update(),
introduced by the commit 9e50bc14a7f58b5d8a55973b2d69355852ae2dae (ACPI /
battery: Accelerate battery resume callback)]

[naszar &lt;naszar@ya.ru&gt;: backport to 3.14.5]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=75581
Reported-and-tested-by: naszar &lt;naszar@ya.ru&gt;
Cc: All applicable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI video: ignore BIOS backlight value for HP dm4</title>
<updated>2014-07-09T17:51:22+00:00</updated>
<author>
<name>Gustavo Maciel Dias Vieira</name>
<email>gustavo@sagui.org</email>
</author>
<published>2013-03-04T15:23:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=badd9b71c5651a687d042966a5fa8d195e9cffe4'/>
<id>badd9b71c5651a687d042966a5fa8d195e9cffe4</id>
<content type='text'>
commit 771d09b3c4c45d4d534a83a68e6331b97fd82e15 upstream.

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.

Signed-off-by: Gustavo Maciel Dias Vieira &lt;gustavo@sagui.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
[wyj: Backported to 3.4: adjust context]
Signed-off-by: Yijing Wang &lt;wangyijing@huawei.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 771d09b3c4c45d4d534a83a68e6331b97fd82e15 upstream.

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.

Signed-off-by: Gustavo Maciel Dias Vieira &lt;gustavo@sagui.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
[wyj: Backported to 3.4: adjust context]
Signed-off-by: Yijing Wang &lt;wangyijing@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI video: ignore BIOS initial backlight value for HP 1000</title>
<updated>2014-07-09T17:51:21+00:00</updated>
<author>
<name>Alex Hung</name>
<email>alex.hung@canonical.com</email>
</author>
<published>2013-05-06T08:23:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0e4337b79778174128fcd785f353047384499d3e'/>
<id>0e4337b79778174128fcd785f353047384499d3e</id>
<content type='text'>
commit 4ef366c583d6180b1c951147869ee5a3038834f2 upstream.

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.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 4ef366c583d6180b1c951147869ee5a3038834f2 upstream.

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Add "Asus UL30A" to ACPI video detect blacklist</title>
<updated>2014-07-09T17:51:21+00:00</updated>
<author>
<name>Bastian Triller</name>
<email>bastian.triller@gmail.com</email>
</author>
<published>2013-05-19T11:52:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=047cce410d083cf08de91bf76aa9bbdae989a285'/>
<id>047cce410d083cf08de91bf76aa9bbdae989a285</id>
<content type='text'>
commit c8f6d8351ba8c89d5cd4c562552ec7ec29274e31 upstream.

Like on UL30VT, the ACPI video driver can't control backlight correctly on
Asus UL30A.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30A" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30A" rather than ACPI
video driver.

Signed-off-by: Bastian Triller &lt;bastian.triller@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.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 c8f6d8351ba8c89d5cd4c562552ec7ec29274e31 upstream.

Like on UL30VT, the ACPI video driver can't control backlight correctly on
Asus UL30A.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30A" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30A" rather than ACPI
video driver.

Signed-off-by: Bastian Triller &lt;bastian.triller@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Add "Asus UL30VT" to ACPI video detect blacklist</title>
<updated>2014-07-09T17:51:21+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2012-11-30T12:02:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=622c5c1435caee7f023de2e422f8e33d3996b9de'/>
<id>622c5c1435caee7f023de2e422f8e33d3996b9de</id>
<content type='text'>
commit d0c2ce16bec0afa6013b4c5220ca4c9c67210215 upstream.

The ACPI video driver can't control backlight correctly on
Asus UL30VT.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30VT" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30VT" rather than ACPI
video driver.

References: https://bugzilla.kernel.org/show_bug.cgi?id=32592
Reported-by: Alex Williamson &lt;alex.williamson@redhat.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.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 d0c2ce16bec0afa6013b4c5220ca4c9c67210215 upstream.

The ACPI video driver can't control backlight correctly on
Asus UL30VT.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30VT" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30VT" rather than ACPI
video driver.

References: https://bugzilla.kernel.org/show_bug.cgi?id=32592
Reported-by: Alex Williamson &lt;alex.williamson@redhat.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>acpi/video_detect: blacklist samsung x360</title>
<updated>2014-07-09T17:51:21+00:00</updated>
<author>
<name>Corentin Chary</name>
<email>corentin.chary@gmail.com</email>
</author>
<published>2012-06-13T07:32:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=89c9afdbdcfdc720fa6ce5acf3745dda6e81a7db'/>
<id>89c9afdbdcfdc720fa6ce5acf3745dda6e81a7db</id>
<content type='text'>
commit 084940d5b101e9ca91a689eb5048151b14076839 upstream.

On Samsung X360, the BIOS will set a flag (VDRV) if the generic
ACPI backlight device is used. This flag will definitively break
the backlight interface (even the vendor interface) untill next
reboot. It's why we should prevent video.ko from being used here
and we can't rely on a later call to acpi_video_unregister().

Signed-off-by: Corentin Chary &lt;corentin.chary@gmail.com&gt;
Signed-off-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.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 084940d5b101e9ca91a689eb5048151b14076839 upstream.

On Samsung X360, the BIOS will set a flag (VDRV) if the generic
ACPI backlight device is used. This flag will definitively break
the backlight interface (even the vendor interface) untill next
reboot. It's why we should prevent video.ko from being used here
and we can't rely on a later call to acpi_video_unregister().

Signed-off-by: Corentin Chary &lt;corentin.chary@gmail.com&gt;
Signed-off-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Yijing Wang &lt;wangyijing@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: Fix conflict between customized DSDT and DSDT local copy</title>
<updated>2014-07-01T03:01:32+00:00</updated>
<author>
<name>Lv Zheng</name>
<email>lv.zheng@intel.com</email>
</author>
<published>2014-05-12T07:50:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0992ba402355b4aca62a74c915f5d787210ef1b5'/>
<id>0992ba402355b4aca62a74c915f5d787210ef1b5</id>
<content type='text'>
commit 73577d1df8e1f31f6b1a5eebcdbc334eb0330e47 upstream.

This patch fixes the following issue:
If DSDT is customized, no local DSDT copy is needed.

References: https://bugzilla.kernel.org/show_bug.cgi?id=69711
Signed-off-by: Enrico Etxe Arte &lt;goitizena.generoa@gmail.com&gt;
Signed-off-by: Lv Zheng &lt;lv.zheng@intel.com&gt;
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 73577d1df8e1f31f6b1a5eebcdbc334eb0330e47 upstream.

This patch fixes the following issue:
If DSDT is customized, no local DSDT copy is needed.

References: https://bugzilla.kernel.org/show_bug.cgi?id=69711
Signed-off-by: Enrico Etxe Arte &lt;goitizena.generoa@gmail.com&gt;
Signed-off-by: Lv Zheng &lt;lv.zheng@intel.com&gt;
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / blacklist: Add dmi_enable_osi_linux quirk for Asus EEE PC 1015PX</title>
<updated>2014-06-07T23:02:03+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2014-05-05T09:38:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bb09378539c61d236a373c1765f968a155a291cd'/>
<id>bb09378539c61d236a373c1765f968a155a291cd</id>
<content type='text'>
commit f6e6e1b9fee88c90586787b71dc49bb3ce62bb89 upstream.

Without this this EEE PC exports a non working WMI interface, with this it
exports a working "good old" eeepc_laptop interface, fixing brightness control
not working as well as rfkill being stuck in a permanent wireless blocked
state.

This is not an ideal way to fix this, but various attempts to fix this
otherwise have failed, see:

References: https://bugzilla.redhat.com/show_bug.cgi?id=1067181
Reported-and-tested-by: lou.cardone@gmail.com
Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 f6e6e1b9fee88c90586787b71dc49bb3ce62bb89 upstream.

Without this this EEE PC exports a non working WMI interface, with this it
exports a working "good old" eeepc_laptop interface, fixing brightness control
not working as well as rfkill being stuck in a permanent wireless blocked
state.

This is not an ideal way to fix this, but various attempts to fix this
otherwise have failed, see:

References: https://bugzilla.redhat.com/show_bug.cgi?id=1067181
Reported-and-tested-by: lou.cardone@gmail.com
Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / processor: Rework processor throttling with work_on_cpu()</title>
<updated>2014-03-11T23:10:01+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2014-02-26T13:03:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1d0230273dea6597819c4fe9f64f5bb891241578'/>
<id>1d0230273dea6597819c4fe9f64f5bb891241578</id>
<content type='text'>
commit f3ca4164529b875374c410193bbbac0ee960895f upstream.

acpi_processor_set_throttling() uses set_cpus_allowed_ptr() to make
sure that the (struct acpi_processor)-&gt;acpi_processor_set_throttling()
callback will run on the right CPU.  However, the function may be
called from a worker thread already bound to a different CPU in which
case that won't work.

Make acpi_processor_set_throttling() use work_on_cpu() as appropriate
instead of abusing set_cpus_allowed_ptr().

Reported-and-tested-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 f3ca4164529b875374c410193bbbac0ee960895f upstream.

acpi_processor_set_throttling() uses set_cpus_allowed_ptr() to make
sure that the (struct acpi_processor)-&gt;acpi_processor_set_throttling()
callback will run on the right CPU.  However, the function may be
called from a worker thread already bound to a different CPU in which
case that won't work.

Make acpi_processor_set_throttling() use work_on_cpu() as appropriate
instead of abusing set_cpus_allowed_ptr().

Reported-and-tested-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Filter the _BCL table for duplicate brightness values</title>
<updated>2014-03-11T23:10:01+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2014-02-13T15:32:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b0b0c264549a424a453bf21ba41941db83f0899b'/>
<id>b0b0c264549a424a453bf21ba41941db83f0899b</id>
<content type='text'>
commit bd8ba20597f0cfef3ef65c3fd2aa92ab23d4c8e1 upstream.

Some devices have duplicate entries in there brightness levels table, ie
on my Dell Latitude E6430 the table looks like this:

[    3.686060] acpi backlight index   0, val 80
[    3.686095] acpi backlight index   1, val 50
[    3.686122] acpi backlight index   2, val 5
[    3.686147] acpi backlight index   3, val 5
[    3.686172] acpi backlight index   4, val 5
[    3.686197] acpi backlight index   5, val 5
[    3.686223] acpi backlight index   6, val 5
[    3.686248] acpi backlight index   7, val 5
[    3.686273] acpi backlight index   8, val 6
[    3.686332] acpi backlight index   9, val 7
[    3.686356] acpi backlight index  10, val 8
[    3.686380] acpi backlight index  11, val 9
etc.

Notice that brightness values 0-5 are all mapped to 5. This means that
if userspace writes any value between 0 and 5 to the brightness sysfs attribute
and then reads it, it will always return 0, which is somewhat unexpected.

This is a problem for ie gnome-settings-daemon, which uses read-modify-write
logic when the users presses the brightness up or down keys. This is done
this way to take brightness changes from other sources into account.

On this specific laptop what happens once the brightness has been set to 0,
is that gsd reads 0, adds 5, writes 5, and on the next brightness up key press
again reads 0, so things get stuck at the lowest brightness setting.

Filtering out the duplicate table entries, makes any write to brightness
read back as the written value as one would expect, fixing this.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Reviewed-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit bd8ba20597f0cfef3ef65c3fd2aa92ab23d4c8e1 upstream.

Some devices have duplicate entries in there brightness levels table, ie
on my Dell Latitude E6430 the table looks like this:

[    3.686060] acpi backlight index   0, val 80
[    3.686095] acpi backlight index   1, val 50
[    3.686122] acpi backlight index   2, val 5
[    3.686147] acpi backlight index   3, val 5
[    3.686172] acpi backlight index   4, val 5
[    3.686197] acpi backlight index   5, val 5
[    3.686223] acpi backlight index   6, val 5
[    3.686248] acpi backlight index   7, val 5
[    3.686273] acpi backlight index   8, val 6
[    3.686332] acpi backlight index   9, val 7
[    3.686356] acpi backlight index  10, val 8
[    3.686380] acpi backlight index  11, val 9
etc.

Notice that brightness values 0-5 are all mapped to 5. This means that
if userspace writes any value between 0 and 5 to the brightness sysfs attribute
and then reads it, it will always return 0, which is somewhat unexpected.

This is a problem for ie gnome-settings-daemon, which uses read-modify-write
logic when the users presses the brightness up or down keys. This is done
this way to take brightness changes from other sources into account.

On this specific laptop what happens once the brightness has been set to 0,
is that gsd reads 0, adds 5, writes 5, and on the next brightness up key press
again reads 0, so things get stuck at the lowest brightness setting.

Filtering out the duplicate table entries, makes any write to brightness
read back as the written value as one would expect, fixing this.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Reviewed-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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