8086:0106 Backlight control regression

[pqwoerituytrueiwoq]

Laptop: ASUS A54C-NB91 with BIOS version 210 After the 3.6 kernel controlling the backlight via software (like xbacklight and the brightness applet) no longer works as intended (attempting to get brightness alters the brightness). This was not a Issue on the older BIOS version (207), but downgrading that is not possible, and ASUS will not fix it stating the typical we don't support linux on this model On the 3.6 kernel with the latest BIOS the backlight can't be controlled via the fn+brightness keys, that still works on the 3.7 kernel and up i have never had the fn+brightness keys ever update /sys/class/backlight/acpi_video0/brightness under any tested scenario.

I have tested Kernel versions 3.8.1-030801, 3.8.0-8, 3.7.10-030710, and 3.6.11-030611 today on raring without acpi_backlight=vendor. I had the exact same results as when i did the test earlier in raring and quantal (see PDF file in attachment). The attachment contains the following files (all system generated files are from this install)
Detailed test.pdf
dmesg_3.6.11-030611-generic
dmesg_3.7.10-030710-generic
dmesg_3.8.0-8-generic
dmesg_3.8.1-030801-generic
lspci_very_verbose
syslog

WORKAROUND: One may choose a value from 0 (completely off) to 4882 (100%) works in increments of 2:
echo 100 | sudo tee /sys/class/backlight/intel_backlight/brightness

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: linux-image-3.8.0-8-generic 3.8.0-8.17
ProcVersionSignature: Ubuntu 3.8.0-8.17-generic 3.8.0
Uname: Linux 3.8.0-8-generic x86_64
ApportVersion: 2.9-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: chad 1708 F.... xfce4-volumed
                      chad 1722 F.... pulseaudio
 /dev/snd/pcmC0D0p: chad 1722 F...m pulseaudio
CurrentDmesg:

Date: Fri Mar 1 11:31:52 2013
HibernationDevice: RESUME=UUID=a974f07b-dcae-4886-8ddb-e5a48219f891
InstallationDate: Installed on 2013-03-01 (0 days ago)
InstallationMedia: Xubuntu 13.04 "Raring Ringtail" - Alpha amd64 (20130301)
MachineType: ASUSTeK Computer Inc. K54C
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-8-generic root=UUID=5c6a915b-d2e5-4746-9c09-657e51145ad6 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.8.0-8-generic N/A
 linux-backports-modules-3.8.0-8-generic N/A
 linux-firmware 1.103
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/23/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: K54C.210
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: K54C
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.asset.tag: ATN12345678901234567
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrK54C.210:bd10/23/2012:svnASUSTeKComputerInc.:pnK54C:pvr1.0:rvnASUSTeKComputerInc.:rnK54C:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr1.0:
dmi.product.name: K54C
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.8 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.9-rc1-raring/

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

RC1 is still missing 3 of the 4 debs, i don't think it would be possible till the other 3 are there
i have tested this one, if that matters
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.8.2-raring/

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

for the record it is not fixed in 3.8.2, probably should have mentioned that instead of filling your in boxes with emails
for reference:
http://ubuntuforums.org/showthread.php?t=2122160
sorry about the 2 for 1 email

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

also effects 3.8.0.10 if that matters

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

confirmed in 3.9.0-030900rc1-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

This test was done on 3.9.0-030900rc1-generic
if it matters any value from 0 (completely off) to 4882 (100%) works for this, increments of 2 have a effect
echo 100 | sudo tee /sys/class/backlight/intel_backlight/brightness
it is like god mode for the back light level

the lowest the fn+brightness keys allow is a level of 1000 in /sys/class/backlight/intel_backlight/brightness
neither /sys/class/backlight/intel_backlight/brightness nor /sys/class/backlight/acpi_backlight/brightness change when using the brightness keys
i think if the system could query the backlight without altering it, it would return to its working state like in 3.6.11
would be nice if the fn keys would synchronize with what the software sets the backlight to (never worked even on the old bios)
as long as software like xbacklight and the xfce4-brightness-plugin can function properly that is good enough for me

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

Confirmed in 3.8.0-11-generic

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

ok i am confused where do i send the email to?
should i attached the output of the command as files?
can i use thunderbird to send it with it set to send in html and plain text?

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

Confirmed in 3.9.0-030900rc2-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

Confirmed in 3.8.0-12-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

reported upstream (hopefully i did it right)
https://bugzilla.kernel.org/show_bug.cgi?id=55161

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

Confirmed in 3.8.3-030803-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

I made a recording of the issue, sorry my webcam sucks, i was not able to get vlc to flip the video playback from the webcam to compensate for the mirror, but its only purpose was showing the backlight response

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

Confirmed in 3.9.0-030900rc3-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

confirmed in 3.9.0-030900rc4-generic
confirmed in 3.8.4-030804-generic
confirmed in 3.8.0-14-generic

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

confirmed in 3.9.0-030900rc5-generic
confirmed in 3.9.0-030900rc6-generic

The kernel boot parameter acpi_osi="!Windows 2012" eliminates the regression
example usage in /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT='quiet splash acpi_osi="!Windows 2012"'

[Robert Rojas (roberthrojasq)]

I don't think the kernel is related, because I tested with kernel 3.5(it worked well with Ubuntu 12.10, with "acpi_backlight=vendor") and had the same problem. I'm using 13.04 and Acer Aspire 4332. If I do "sudo su" and "echo (brightness value) > /sys/class/backlight/intel_backlight/brightness" in the command line it works. The Fn ← & → keys worked only if add "acpi_osi=Linux" to GRUB_CMDLINE_LINUX_DEFAULT. However I couldn't set bright from System Configuration.

[pqwoerituytrueiwoq (pqwoerituytrueiwoq)]

This is related to the kernel interracting with the bios that "caters to windows 8"
this issued shows up after a bios update i was able to get software to control the backlight properly on the 3.6.11 kernel, but not on anything newer than that
see the upstream bug report for more info

i never cared for using the fn brightness keys to control my brightness, i only use software to manage it