8086:2a42 [Acer Aspire 5736Z] Screen too dark, no backlight, unusable X

[Otto Kekäläinen]

I just did a fresh install of Precise on a Acer Aspire 5736Z with intel GMA 4500. When I booted the installer from a USB, the screen is OK in the boot menu (non-X) but as soon as X starts, the backlight of the screen turns off making the screen almost black, and thus unusable.

Pressing Fn+Left Arrow does not increase screen brightness. Also pressing Fn+F6 (backlight on/off does not work).

At the moment Precise is impossible to install on Acer Aspire 5736Z by a regular user. The laptop worked fine with Ubuntu 10.04, so this is a regression.

Expected result: screen brightness should be higher and the user should be able to see what is on the screen.

Workaround: If I boot the installer with kernel option acpi=off, the screen is still by default to dark, but pressing Fn+Left Arrow turns the backlight on and X becomes usable.

After installation "acpi=off" is not remembered by the system, so I have to manually insert the option into Grub to make the change presistent and the user who boots the laptop needs to press Fn+Left Arrow at each boot after X has started (as it starts by default with backlight off and screen way too dark).

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xorg 1:7.6+7ubuntu7
ProcVersionSignature: Ubuntu 3.2.0-2.5-generic 3.2.0-rc3
Uname: Linux 3.2.0-2-generic i686
.tmp.unity.support.test.0:

ApportVersion: 1.90-0ubuntu1
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,regex,snap,mousepoll,imgpng,resize,unitymtgrabhandles,place,animation,move,grid,vpswitch,gnomecompat,compiztoolbox,wall,session,workarounds,expo,ezoom,fade,scale,unityshell]
CompositorRunning: compiz
Date: Sun Jan 1 15:03:36 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:048a]
   Subsystem: Acer Incorporated [ALI] Device [1025:048a]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20111129.1)
MachineType: Acer Aspire 5736Z
ProcEnviron:
 PATH=(custom, no user)
 LANG=fi_FI.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-2-generic root=UUID=743be841-a164-4092-9bd9-36acdcae5994 ro quiet splash vt.handoff=7 acpi=off noapic nolapic
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/17/2010
dmi.bios.vendor: Acer
dmi.bios.version: V1.03
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: JE51_MV
dmi.board.vendor: Acer
dmi.board.version: V1.03
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.03
dmi.modalias: dmi:bvnAcer:bvrV1.03:bd08/17/2010:svnAcer:pnAspire5736Z:pvrV1.03:rvnAcer:rnJE51_MV:rvrV1.03:cvnAcer:ct10:cvrV1.03:
dmi.product.name: Aspire 5736Z
dmi.product.version: V1.03
dmi.sys.vendor: Acer
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu7
version.libdrm2: libdrm2 2.4.27-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu4
version.xserver-xorg-core: xserver-xorg-core 2:1.10.4-1ubuntu5
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu3
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1

[Otto Kekäläinen (otto)]

I noticed that running manually
xrandr --output LVDS1 --set BACKLIGHT 0
makes the screen brightness maximum.

If I boot without acpi=off and run the xrandr-command, nothing happends. None of the Fn-key work either as acpi is on, so I guess the ACPI is broken.

To make the screen as dim as possible, run
xrandr --output LVDS1 --set BACKLIGHT 2948310

Maybe the range should be the other way around, 0 as minimum lightness?

$ xrandr --prop
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
 EDID:
  00ffffffffffff000daf991500000000
  07140103802213780a3d9594564f8e28
  26505400000001010101010101010101
  0101010101017a1d56d250001e303c28
  360058c110000018000000fe004e3135
  3642332d4c30420a2020000000fe0043
  4d4f0a202020202020202020000000fe
  004e31353642332d4c30420a20200048
 BACKLIGHT: 1 (0x00000001) range: (0,2948310)
 Backlight: 1 (0x00000001) range: (0,2948310)
 scaling mode: Full aspect
  supported: None Full Center Full aspect
   1366x768 60.0*+
   1360x768 59.8 60.0
   1024x768 60.0
   800x600 60.3 56.2
   640x480 59.9

As a workaround I tried to add
xrandr --output LVDS1 --set BACKLIGHT 0 -display :0
to /etc/rc.local but it does not work (error says cookie mismatch).

A less optimal workaround I added the command to the Gnome session, but LDM starts out dimmed, so the sole user of the laptop has to enter their password blindly (screen is to dark to see almost anything).

[Otto Kekäläinen (otto)]

I added now an external monitor to the laptop so that I could investigate what state its is in when booted withouth "acpi=off". It
turns out that with ACPI enabled, the xrandr brightness range is 0-9:

$ xrandr --prop
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
 EDID:
  00ffffffffffff000daf991500000000
  07140103802213780a3d9594564f8e28
  26505400000001010101010101010101
  0101010101017a1d56d250001e303c28
  360058c110000018000000fe004e3135
  3642332d4c30420a2020000000fe0043
  4d4f0a202020202020202020000000fe
  004e31353642332d4c30420a20200048
 BACKLIGHT: 9 (0x00000009) range: (0,9)
 Backlight: 9 (0x00000009) range: (0,9)

However the commands dont make any difference, as brightness does not change (screen stays almost black):
$ xrandr --output LVDS1 --set BACKLIGHT 0
$ xrandr --output LVDS1 --set BACKLIGHT 5
$ xrandr --output LVDS1 --set BACKLIGHT 9

lsmod shows that the module "acer_wmi" is loaded. Unloading it does not make a difference. All hotkeys seem to work all the time.

The page http://www.mjmwired.net/kernel/Documentation/laptops/acer-wmi.txt says there should be a directory /sys/devices/platform/acer-wmi/backlight/acer-wmi/, but that does not exist on this machine:
/sys/devices/platform/acer-wmi$ ls
driver interface modalias power rfkill subsystem uevent

Playing around a little bit I noticed that in
sudo -s
echo "1" > /sys/class/backlight/intel_backlight/brightness
# makes the screen bright
echo "2948310" > /sys/class/backlight/intel_backlight/brightness
# makes the screen dark

I added the first line to /etc/rc.local and this works as a temporary fix. The Fn+Arrow buttons however do not change the brightness.

[Otto Kekäläinen (otto)]

I now also got the Fn+Arrow-buttons working by adding the kernel option "acpi_backlight=vendor" if found while googling around.

Make change permament by editing row in /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
and then run "sudo update-grub"

[Travis Monteith (travmon69)]

I have acer aspire 5734z with gma 4500 running archlinux. best solution for me is adding GRUB_CMDLINE_LINUX="acpi_osi=Linux" to /etc/default/grub then update grub. still starts dark but brightness keys work. it is kernel issue not the operating system. See here https://lkml.org/lkml/2011/4/5/172 I think "acpi_osi=" works also

[Bryce Harrington (bryce)]

Likely to be either kernel or perhaps gnome-power-manager.

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

You can update to the latest development kernel by simply running the following commands in a terminal window:

    sudo apt-get update
    sudo apt-get upgrade

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

If you want this bot to quit automatically requesting kernel tests, add a tag named: bot-stop-nagging.

 Thank you for your help, we really do appreciate it.

[sma (m-0622)]

I guess this bug is the same issue as discussed in this bugreport: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/826386 (No backlight display Acer Aspire 5734Z).

Maybe the workaround described in #33 (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/826386/comments/33) still works. See also http://ubuntuforums.org/showpost.php?p=10740136&postcount=3

[Brad Figg (brad-figg)]

@otto,

Can you take a look at the suggestion in #8 and see if that workaround does indeed help?

[Otto Kekäläinen (otto)]

@bradd,

The laptop in question is not my own, so I'm not sure when I'll be able to visit it and test the other workarounds (#5 and #8). The workaround in #4 has been working, so from this particular users point of view the situation is not critical. But eventually I'll test the other workarounds too, so you'll have more data on what are the options to fix this bug.

[sma (m-0622)]

An additional problem is, when the computer wakes up after hibernate/standby, the screen will stay black.

I found three workarounds, that promise to solve this problem:

1) http://ubuntuforums.org/showthread.php?p=11423423#post11423423

2) http://ubuntuforums.org/showpost.php?p=11578848&postcount=4

3) http://linux-on-acer-aspire-5732z.blogspot.com/2011/06/backlight-workaround-for-linux-mint-11.html

(P.S: Same issue also discussed in this thread: https://bugs.launchpad.net/unity/+bug/744187 )

[Brad Figg (brad-figg)]

@sma,

One bug per bug report. Please file a new bug on the hibernate issue.

[Otto Kekäläinen (otto)]

@brad-figg: I did the tests you asked me.

I now ran dist-upgrade and booted with the Acer laptop that suffers from this issue. It turned out the old workaround in comment #4 stopped working in the new kernel 3.2.0-18, that is in /etc/default/grub line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

I tried replacing it with
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="
and
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"

The second one was not good, as the Fn+Arrow right increased the backlight and Arrow left vice versa, but on this keyboard the buttons should go the other way around. However the former option responded to the buttons the right way.

So if you are running a similar Acer laptop, this my recommended solution to get the Fn-buttons working is adding the line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="
to your /etc/default/grub and then run "sudo update-grub"

This is however only 50 % of the solution. When the computer starts you probably want to see the screen by default without pressing Fn+Arrow left first.

Therefore add to you /etc/rc.local file the line

echo "1" > /sys/class/backlight/intel_backlight/brightness

(put it just above the exit 0 line)

The workaround in Comment #33 for bug #826386 suggets adding to rc.local the line "sudo setpci -s 00:02.0 F4.B=0", but I think my version is more verbose and robust to errors.

Somebody with the skills should write a patch that detects this laptop make and inserts these two lines in grub and rc.local that fixes the issue.

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

You can update to the latest development kernel by simply running the following commands in a terminal window:

    sudo apt-get update
    sudo apt-get dist-upgrade

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

If you want this bot to quit automatically requesting kernel tests, add a tag named: bot-stop-nagging.

 Thank you for your help, we really do appreciate it.

[jhfhlkjlj (fdsuufijjejejejej-deactivatedaccount)]

This is actually a duplicate of the rather old bug 765438. Marking as such.

[penalvch (penalvch)]

Otto Kekäläinen, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, 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 (not the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. 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-v3.13-rc1

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

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.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Jonatã Bolzan Loss (jbopen)]

Bug still present in Ubuntu 14.04.

[penalvch (penalvch)]

jonata, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs