luminosity screen on a laptop cannot be set

[Marc Bristiel]

After upgrade from karmic to lucid, luminosity cannot be set on a laptop (Asus Pro 5JI).

When pressing the luminosity keys, dmesg send the following output :

8<-----------------------------------
[ 209.309032] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (00000005D) is beyond end of object (20090903/exoparg2-445)
[ 209.309047] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node f701bb28), AE_AML_BUFFER_LIMIT
[ 209.309115] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node f7016cd8), AE_AML_BUFFER_LIMIT
[ 209.309186] ACPI Error: Evaluating _BCM failed (20090903/video-528)
[ 209.309192] ACPI: Failed to switch the brightness
[ 209.314634] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000064) is beyond end of object (20090903/exoparg2-445)
[ 209.314643] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node f701bb28), AE_AML_BUFFER_LIMIT
[ 209.314683] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node f7016cd8), AE_AML_BUFFER_LIMIT
[ 209.314723] ACPI Error: Evaluating _BCM failed (20090903/video-528)
[ 209.315943] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (00000005D) is beyond end of object (20090903/exoparg2-445)
[ 209.315952] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node f701bb28), AE_AML_BUFFER_LIMIT
[ 209.315992] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node f7016cd8), AE_AML_BUFFER_LIMIT
[ 209.316489] ACPI Error: Evaluating _BCM failed (20090903/video-528)
[ 209.325119] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000064) is beyond end of object (20090903/exoparg2-445)
[ 209.325128] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node f701bb28), AE_AML_BUFFER_LIMIT
[ 209.325167] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node f7016cd8), AE_AML_BUFFER_LIMIT
[ 209.325207] ACPI Error: Evaluating _BCM failed (20090903/video-528)
8<-----------------------------------

Error persists even after a reboot.

[Thorsten Hirsch (t-hirsch)]

Seems to be an issue with kernels > 2.6.31.
I just installed vanilla kernel 2.6.34-rc4 and used karmic's default configuration. When booting I have the similar messages in dmesg:

[ 19.230795] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000066) is beyond end of object (20100121/exoparg2-445)
[ 19.230809] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013b640060), AE_AML_BUFFER_LIMIT
[ 19.230872] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88013b63a220), AE_AML_BUFFER_LIMIT
[ 19.230939] ACPI Error: Evaluating _BCM failed (20100121/video-536)
[ 19.231895] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000066) is beyond end of object (20100121/exoparg2-445)
[ 19.231907] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013b640060), AE_AML_BUFFER_LIMIT
[ 19.231969] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88013b63a220), AE_AML_BUFFER_LIMIT
[ 19.232033] ACPI Error: Evaluating _BCM failed (20100121/video-536)
[ 29.605041] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000066) is beyond end of object (20100121/exoparg2-445)
[ 29.605054] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013b640060), AE_AML_BUFFER_LIMIT
[ 29.605116] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88013b63a220), AE_AML_BUFFER_LIMIT
[ 29.605181] ACPI Error: Evaluating _BCM failed (20100121/video-536)

Hardware: Asus UL30a with intel chipsets (including video). There appears NO new dmesg entry when pressing the brightness keys. And it works, I can change the brightness w/o problems.

[Yuri Klimenko (yurik7)]

I have this problem also on fresh Ubuntu 10.04, hardware: asus p81ij

[Sebastian Carcamo (hecarcam)]

I have the same problem.

I installed cleanly Ubuntu 10.04

Hardware : Compaq 515

[Gianluigi Avella (giangi1983)]

I have a similar problem.

I installed cleanly Ubuntu 10.04 AMD64

Hardware : Sony Vaio VPCEB1M1E/BJ with Video hardware ATI Mobility Radeon HD5650 1GB

With the poperty driver don't work the luminosity change but with the open drive it's work

[Nuno Salgado (nuno-salgado)]

Same problem with Asus K50IJ.

10.04 - Linux version 2.6.32-22-generic (buildd@rothera) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #33-Ubuntu SMP Wed Apr 28 13:27:30 UTC 2010 (Ubuntu 2.6.32-22.33-generic 2.6.32.11+drm33.2)

[Andrew Fluth (afluth)]

I have the same issue with my Asus UL20A

ACPI Exception: AE_AML_BUFFER_LIMIT, Index (00000005E) is beyond end of object (20090903/exoparg2-445)
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88007bb34ec0), AE_AML_BUFFER_LIMIT
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88007bb2f200), AE_AML_BUFFER_LIMIT
ACPI Error: Evaluating _BCM failed (20090903/video-528)
ACPI: Failed to switch the brightness
ACPI Exception: AE_AML_BUFFER_LIMIT, Index (00000005E) is beyond end of object (20090903/exoparg2-445)
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88007bb34ec0), AE_AML_BUFFER_LIMIT
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88007bb2f200), AE_AML_BUFFER_LIMIT
ACPI Error: Evaluating _BCM failed (20090903/video-528)
ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000064) is beyond end of object (20090903/exoparg2-445)
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88007bb34ec0), AE_AML_BUFFER_LIMIT
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88007bb2f200), AE_AML_BUFFER_LIMIT
ACPI Error: Evaluating _BCM failed (20090903/video-528)
ACPI Exception: AE_AML_BUFFER_LIMIT, Index (000000064) is beyond end of object (20090903/exoparg2-445)
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88007bb34ec0), AE_AML_BUFFER_LIMIT
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff88007bb2f200), AE_AML_BUFFER_LIMIT
ACPI Error: Evaluating _BCM failed (20090903/video-528)

[Jeremy Foshee (jeremyfoshee)]

Hi Marc,

Please be sure to confirm this issue exists with the latest development release of Ubuntu. ISO CD images are available from http://cdimage.ubuntu.com/releases/ . If the issue remains, please run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 566193

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

    [This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[Aurélien Gâteau (agateau)]

AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: VT1708S Analog [VT1708S Analog]
   Subdevices: 2/2
   Subdevice #0: subdevice #0
   Subdevice #1: subdevice #1
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: VT1708S Analog [VT1708S Analog]
   Subdevices: 2/2
   Subdevice #0: subdevice #0
   Subdevice #1: subdevice #1
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: aurelien 1824 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfe9f4000 irq 44'
   Mixer name : 'VIA VT1708S'
   Components : 'HDA:11060397,10431111,00100000'
   Controls : 20
   Simple ctrls : 13
DistroRelease: Ubuntu 10.10
HibernationDevice: RESUME=UUID=06f1ef32-476d-4a2c-a878-471f073766b4
InstallationMedia: Kubuntu 10.10 "Maverick Meerkat" - Alpha amd64 (20100622)
MachineType: ASUSTeK Computer Inc. P81IJ
Package: linux (not installed)
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.35-4-generic root=UUID=863c29e5-f257-412c-8ea0-51b0db58a5e1 ro quiet splash
ProcEnviron:
 LANGUAGE=
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.35-4.5-generic 2.6.35-rc3
Regression: No
RelatedPackageVersions: linux-firmware 1.37
Reproducible: Yes
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
Tags: maverick suspend resume needs-upstream-testing
Uname: Linux 2.6.35-4-generic x86_64
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
dmi.bios.date: 12/04/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 203
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: P81IJ
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.:bvr203:bd12/04/2009:svnASUSTeKComputerInc.:pnP81IJ:pvr1.0:rvnASUSTeKComputerInc.:rnP81IJ:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr1.0:
dmi.product.name: P81IJ
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.

[Aurélien Gâteau (agateau)]

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[Aurélien Gâteau (agateau)]

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[Marc Bristiel (lgmdmdlsr)]

More information : when passing the parameter "acpi_backlight=vendor" to the kernel at boot time, user can change luminosity by using the "fn" key on the keyboard ("light+" and "light-").
However, dmesg continues in sending errors and GNOME light applet cannot be used to set luminosity.

[Ryan (ubuntu-draziw)]

Affects me too UL30A-X5. dmidecode shows as:
Manufacturer: ASUSTeK Computer Inc. Product Name: UL30A

Confirm it was an issue with the newest CD image, and still occurs after fully updating everything...
# uname -a
Linux laptop 2.6.32-23-generic-pae #37-Ubuntu SMP Fri Jun 11 09:26:55 UTC 2010 i686 GNU/Linux

[Ryan (ubuntu-draziw)]

Patch is upstream in 2.6.33-rc2 and the following shows what is reported as a work around until then.
https://bugzilla.kernel.org/show_bug.cgi?id=14753#c20

[Aurélien Gâteau (agateau)]

I can still reproduce the bug with 2.6.35-19. The workaround mentioned by Ryan works fine here (ASUS P81IJ). I applied it by editing /etc/default/grub and changed the line which says:

  GRUB_CMDLINE_LINUX=""
to:
  GRUB_CMDLINE_LINUX="acpi_osi='\"!Windows 2009\"'"

And ran update-grub

[Aurélien Gâteau (agateau)]

Tested today with mainline kernel (2.6.36-999.201009080908). Here are the results:

(kb means setting brightness with keyboard, applet means setting brightness with Plasma applet)

mainline: kb=good(1) applet=bad
mainline + acpi_osi: kb=good(1) applet=bad
2.6.35-20: kb=bad applet=bad
2.6.35-20 + acpi_osi: kb=good applet=good

(1) In these cases, brightness is adjusted, but the brightness osd does not show up

[Kamil Markowicz (kamil-markowicz)]

I was schocked to find out that this is still an issue in Maverick! As usual, setting GRUB_CMDLINE_LINUX="acpi_osi='\"!Windows 2009\"'" works for me on my Asus UL30A laptop with Intel GPU.

How can we get someone to notice this bug and fix it? I can only imagine how many new Ubuntu users are put off by this and end up dismissing the OS :(.

[Aurélien Gâteau (agateau)]

Still not working with kernel 2.6.38-8-generic. The GRUB_CMDLINE_LINUX="acpi_osi='\"!Windows 2009\"'" workaround does not work anymore.
Workaround of the day is GRUB_CMDLINE_LINUX="acpi_backlight=vendor", and calling update-grub (thanks to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/428910/comments/5).

[Aurélien Gâteau (agateau)]

Actually real workaround of the day is to set GRUB_CMDLINE_LINUX="acpi_backlight=vendor acpi_osi='\"!Windows 2009\"'" otherwise laptop cannot be suspended by closing the lid.

[Kamil Markowicz (kamil-markowicz)]

This is still an issue with 11.04. I cannot believe it! The worst part is, none of the kernel parameter workarounds seem to work for me :(. Who do we have to pay to get this fixed?

[Pasi Tarhonen (pasi-tarhonen)]

Still issue with latest 11.04 kernel from kernel-ppa (2.6.39-0-generic #5~20110427-Ubuntu SMP Wed Apr 27 15:27:41 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux).

Have not tried yet any workaround, because I have same Asus UL30A laptop than Kamil who reported those are not working.

I experienced quite much short (1..30 s) mouse/cursor lockups with earlier kernel 2.6.38-9 but now with 2.6.39 those lockups are rare. I don't know are the lockups related with this bug?

[Pasi Tarhonen (pasi-tarhonen)]

I tested workaround

GRUB_CMDLINE_LINUX="acpi_backlight=vendor acpi_osi='\"!Windows 2009\"'"

with latest 11.04 kernel from kernel-ppa (2.6.39-0-generic #5~20110427-Ubuntu SMP Wed Apr 27 15:27:41 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux).

Workaround works e.g. I am able to change display brightness with function keys (Asus UL30A), but dmesg still prints out various error messages like:

[ 92.320754] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110316/dsutils-763)
[ 92.320767] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node ffff880138e38550), AE_AML_NO_RETURN_VALUE (20110316/psparse-536)
[ 92.320788] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node ffff880138e3fcd0), AE_AML_NO_RETURN_VALUE (20110316/psparse-536)
[ 92.757691] ACPI Error: Result stack is empty! State=ffff880111500400 (20110316/dswstate-98)
[ 92.757710] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110316/dsutils-646)
[ 92.757721] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110316/dsutils-763)
[ 92.757734] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node ffff880138e38550), AE_AML_NO_RETURN_VALUE (20110316/psparse-536)
[ 92.757756] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node ffff880138e3fcd0), AE_AML_NO_RETURN_VALUE (20110316/psparse-536)

I suppose now that those lockups are due MTRR error with video memory allocation, situation is indeed better with 2.6.39 but MTRR error still causes minor "stickiness" of graphics performance every now and then.

[ 0.000000] MTRR default type: uncachable
[ 0.000000] MTRR fixed ranges enabled:
[ 0.000000] MTRR variable ranges enabled:
[ 15.264935] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining
[ 15.264941] [drm] MTRR allocation failed. Graphics performance may suffer.

[nesur (uribepnr)]

I can confirm this bug is still present in 11.04 with a fully up-to-date system, kernel Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 (Ubuntu 2.6.38-8.42-generic 2.6.38.2).

I have an ASUS U81A laptop and backlight brightness was not adjustable with stock settings (it DID worked in Ubuntu 10.04). dmesg shows:

[ 1590.777213] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x000000000000001B) is beyond end of object (20110112/exoparg2-418)
[ 1590.777228] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.777243] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.777259] ACPI Error: Evaluating _BCM failed (20110112/video-365)
[ 1590.777266] ACPI: Failed to switch the brightness
[ 1590.780977] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x000000000000001B) is beyond end of object (20110112/exoparg2-418)
[ 1590.780992] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.781008] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.781024] ACPI Error: Evaluating _BCM failed (20110112/video-365)
[ 1590.782442] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x0000000000000021) is beyond end of object (20110112/exoparg2-418)
[ 1590.782458] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.782473] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.782489] ACPI Error: Evaluating _BCM failed (20110112/video-365)
[ 1590.786929] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x0000000000000021) is beyond end of object (20110112/exoparg2-418)
[ 1590.786943] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.786958] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
[ 1590.786973] ACPI Error: Evaluating _BCM failed (20110112/video-365)

I did the
GRUB_CMDLINE_LINUX="acpi_backlight=vendor"
workaround (no change in ACPI!) and now backlight works. dmesg now shows other errors:

[ 1532.974709] ACPI Error: Result stack is empty! State=ffff88011421b800 (20110112/dswstate-98)
[ 1532.974722] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110112/dsutils-646)
[ 1532.974730] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110112/dsutils-763)
[ 1532.974739] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.DWBL] (Node ffff8801376387f8), AE_AML_NO_RETURN_VALUE (20110112/psparse-536)
[ 1532.974754] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0E] (Node ffff88013763feb0), AE_AML_NO_RETURN_VALUE (20110112/psparse-536)

[penalvch (penalvch)]

Marc Bristiel, could you please confirm this issue exists with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ . If the issue remains, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Please do not test the daily folder, but the one all the way at the bottom. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.11-rc5

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

If you are unable to test the mainline kernel, please comment as to why specifically you were unable to test it and add the following tags:
kernel-unable-to-test-upstream
kernel-unable-to-test-upstream-VERSION-NUMBER

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Marc Bristiel (lgmdmdlsr)]

Since the computer affected by the bug is still run under 12.04 I can't test the dev version.

Bug still exists in 12.04, "Linux [...] 3.2.0-51-generic #77-Ubuntu SMP Wed Jul 24 20:21:10 UTC 2013 i686 i686 i386 GNU/Linux"

And workaround boot parameter "acpi_backlight=vendor" still works.

[Po-Hsu Lin (cypressyew)]

Closing this bug with Won't fix as this kernel / release is no longer supported.
Please feel free to open a new bug report if you're still experiencing this on a newer release (Bionic 18.04.3 / Disco 19.04)
Thanks!