[ASUS-A7K laptop] screen brightness dimmed after kernel update

[Catalin]

Hello,

Following the update from kernel version 3.13.0-34 to 3.13.0-35-generic the screen brightness got a lot dimmer.
The Fn+F5/F6 control keys still work, in that the display gets dimmer and brighter, but the maximum brightness is too low.
When starting ubuntu using the previous kernel release the display brightness is alright.
I've looked around the web for ways to change the display brightness and I checked that both files "/sys/class/backlight/acpi_video0/brightness" and "/sys/class/backlight/radeon_bl0/brightness" have the maximum values, 15 and 255 respectively.

The release I am running is : Ubuntu 14.04.1 LTS
The XORG package version is : 1:7.7+1ubuntu8

Please feel free to contact me for any further information.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xorg 1:7.7+1ubuntu8
ProcVersionSignature: Ubuntu 3.13.0-35.62-generic 3.13.11.6
Uname: Linux 3.13.0-35-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.1-0ubuntu3.3
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: GNOME
Date: Sun Aug 31 11:40:07 2014
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV630/M76 [Mobility Radeon HD 2600] [1002:9581] (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Device [1043:1562]
InstallationDate: Installed on 2014-07-24 (38 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: ASUSTeK Computer Inc. A7K
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-35-generic root=/dev/mapper/vg_a7k-lv_root ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/25/2007
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: A7KAS.2
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: A7K
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrA7KAS.2:bd07/25/2007:svnASUSTeKComputerInc.:pnA7K:pvr1.0:rvnASUSTeKComputerInc.:rnA7K:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr:
dmi.product.name: A7K
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.
version.compiz: compiz 1:0.9.11.2+14.04.20140714-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.52-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.1
version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
xserver.bootTime: Sun Aug 31 11:06:06 2014
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.15.1-0ubuntu2
xserver.video_driver: radeon

[Vda-linux (vda-linux)]

Created attachment 102847
dmesg

I log in as root on a text virtual console.
After about 10 minutes screen blanks.

Surprisingly, pressing a key does *not* unblank the screen!

Machine is still alive (I can ssh into it), and typed keys even reach the console: I can type e.g. "ls -lR /usr" and I see disk indicator blinking, ls process is visible in the ps in ssh session, etc.

This does not happen in X.

This is observed on Lenovo T60, on RHEL7 kernel and also on recent upstream kernel 3.15.5.

Investigation had revealed that VT unblanking code, after all the hard work it done to turn display back on, calls ATOM_LCD_BLOFF (backlight off, numeric value 2) function.

Digging further, I discovered that fb_blank(blank=0) almost at its end calls fb_notifier_call_chain(FB_EVENT_BLANK). Which calls backlight.c::fb_notifier_callback(), which tries to set brightness via radeon_atom_backlight_update_status(), which does
atombios_set_backlight_level(radeon_atom_bl_level()), but radeon_atom_bl_level() is zero (it's an uint8_t, brightness level). So it's essentially atombios_set_backlight_level(0) and it switches backlight off.

In drivers/gpu/drm/radeon/*, bd->props.brightness, surprisingly, is only set in radeon_atom_backlight_init() and radeon_legacy_backlight_init(), all other locations are only reading it. So, if this init code sets it to 0, then VT unblanking code will use this zero value as brightness to restore, causing this bug.

And indeed, that's what happens on the machine exhibiting this bug:

[ 2.301563] radeon_atom_get_backlight_level_from_reg: RADEON_BIOS_2_SCRATCH
[ 2.301633] radeon_atom_get_backlight_level_from_reg: bios_2_scratch:00000000
[ 2.301704] radeon_atom_backlight_init: bd->props.brightness=0
[ 2.301780] radeon_atom_backlight_update_status: atombios_set_back

The full dmesg of the RHEL7 boot with many debug printks added is attached. (Sorry, I started debugging it on RHEL7, I believe mainline does not differ significantly).
It shows the following: After "setterm -blank 1 && sleep 60", VT blanking triggers at ~362 seconds, and at ~370 seconds VT is trying to unblank because of keyboard activity. The bug is evident here:

[ 370.852058] fb_blank: fb_notifier_call_chain(FB_EVENT_BLANK)...
[ 370.852061] fbcon_event_notify: case FB_EVENT_BLANK: fbcon_fb_blanked(blank:0)
[ 370.852063] fbcon_fb_blanked: do_unblank_screen(0)
[ 370.852064] do_unblank_screen: entered on cpu 0
[ 370.852066] do_unblank_screen: !console_blanked on cpu 0
[ 370.852068] backlight: drivers/video/backlight/backlight.c:fb_notifier_callback: backlight_update_status()
[ 370.852071] radeon_atom_backlight_update_status: atombios_set_backlight_level()
[ 370.852072] radeon_atom_bl_level: level = bd->props.brightness:0
[ 370.852074] atombios_set_backlight_level(level:0)
[ 370.852077] atombios_set_backlight_level: atom_execute_table(ATOM_LCD_BLOFF)
^^^^^^^^^^^^^^^^^^^^ THIS TURNS OFF DISPLAY ^^^^^^^^^^^^^^^^^
[ 370.852083] atom_execute_table_locked(index:23,*params:ffff8802) returns 0
[ 370.852085] backlight: drivers/video/backlight/backlight.c:fb_notifier_callback: backlight_update_status()
[ 370.852940] fb_blank returns 0
[ 370.852942] fbcon_blan...

[Vda-linux (vda-linux)]

Created attachment 102852
Debugging messages patch

[agd5f (agd5f)]

*** Bug 70207 has been marked as a duplicate of this bug. ***

[agd5f (agd5f)]

Created attachment 102856
set the default backlight level to something reasonable

Does this patch help?

[Vda-linux (vda-linux)]

(In reply to comment #3)
> Created attachment 102856 [details] [review]
> set the default backlight level to something reasonable
>
> Does this patch help?

Yes, it does.

Maybe add a comment there why this check is necessary?

[agd5f (agd5f)]

Will do.

[David Heidelberg (okias)]

Work perfectly on Toshiba A210-15j!

Tested-by: David Heidelberger <email address hidden>

[David Heidelberg (okias)]

Ok, this fix work, but cause another problem (tested with 3.15.5+patch and 3.16.1).

When display goes off, backlight goes off.
When display goes on, backlight is set to MAX.
When display goes off again, backligh remains MAX.
After pressing key, LCD works, backlight stay at MAX level.
When display goes off, backlight is still MAX.

[Daniel-kirsten-72 (daniel-kirsten-72)]

The above patch causes a problem on my Amilo Xi 2550 (RadeonHD 2600).

The behaviour for kernel-3.14.8-100.fc19 (without patch):

The value of /sys/class/backlight/radeon_bl0/brightness is 0.
Whenever I write something (0-255) to /sys/class/backlight/radeon_bl0/brightness,
the backlight is turned off, and I am not able to turn on the backlight again.
However, I can still shutdown the system (Ctr+Alt+Fx, login as root, and give a
shutdown command.

I can control the backlight by writing values 0-7 to /sys/class/backlight/acpi_video0/brightness.

The behaviour for kernel-3.14.17-100.fc19 (with patch):

The backlight is turned off during the boot up process, when the kernel switches into
graphics mode.
I commented out the lines 233-234 in drivers/gpu/drm/radeon/atombios_encoders.c,
and then, the problem disappeared, i.e., the backlight stays on when the kernel switches
into graphics mode.

Best regards,
Daniel

[Vda-linux (vda-linux)]

(In reply to comment #7)
> Ok, this fix work, but cause another problem (tested with 3.15.5+patch and
> 3.16.1).
>
> When display goes off, backlight goes off.
> When display goes on, backlight is set to MAX.
> When display goes off again, backligh remains MAX.
> After pressing key, LCD works, backlight stay at MAX level.
> When display goes off, backlight is still MAX.

I would say it means that merely treating backlight value of 0 as MAX is not the best idea.

Maybe we need an additional bool variable "failed to read initial BL value, don't ever try to set it", set it if initial read of BL value is 0, and if it is set, never try to change BL level?

[agd5f (agd5f)]

(In reply to comment #7)
> Ok, this fix work, but cause another problem (tested with 3.15.5+patch and
> 3.16.1).
>
> When display goes off, backlight goes off.
> When display goes on, backlight is set to MAX.
> When display goes off again, backligh remains MAX.
> After pressing key, LCD works, backlight stay at MAX level.
> When display goes off, backlight is still MAX.

Does the backlight respond correctly when adjusted via the sysfs blacklight interface?

[Ps (ps-mail)]

I've got the same notebook as Daniel Kirsten, so I've searched for changes in the kernel code, which caused the dark screen. From that point, I've found the patch from Alex Deucher and this bug report.

If I change /sys/class/backlight/radeon_bl0/brightness or /sys/class/backlight/acpi_video0 the display stayes dark.

@Alex
is this what you wanted to know? If not, please let me know, how I could help you to debug this problem!

[Daniel-kirsten-72 (daniel-kirsten-72)]

(In reply to comment #11)
> I've got the same notebook as Daniel Kirsten,

They sold different Amilo Xi 2550, there are even some Amilo Xi 2550 with
an Nvidia graphic card.

> If I change /sys/class/backlight/radeon_bl0/brightness or
> /sys/class/backlight/acpi_video0 the display stayes dark.

I can control brightness by writing 0-7 into
/sys/class/backlight/acpi_video0/brightness

You should comment out lines 233-234 in drivers/gpu/drm/radeon/atombios_encoders.c,
i.e.,

/* if (bd->props.brightness == 0)
    234 bd->props.brightness = RADEON_MAX_BL_LEVEL; */

then it works.

Daniel

[Ps (ps-mail)]

(In reply to comment #12)

Hi Daniel,

correct, before that patch, the display was controllable through /sys/class/backlight/acpi_video0/brightness.

After that patch, the display is always dark.

The only change which was done by Alex, was adding the lines, which you commeted out. (If I understood the code correct, the other two lines, which were removed, are obsolete and not needed).

So if you removed that two lines, then you've got the same code as before and our Amilo (with ATI card) is working fine, but Denys problem will appear again...

[agd5f (agd5f)]

(In reply to comment #11)
> If I change /sys/class/backlight/radeon_bl0/brightness or
> /sys/class/backlight/acpi_video0 the display stayes dark.
>
> @Alex
> is this what you wanted to know? If not, please let me know, how I could
> help you to debug this problem!

Without the patch from this bug report applied (e.g., when your display is working), which, if any, of the blacklight interfaces work? It seems like perhaps your laptop claims to have a GPU controlled backlight, but really uses an external backlight control. Can you attach a copy of your vbios? TO get a copy of your vbios:

(as root)
(use lspci to get the bus id)
cd /sys/bus/pci/devices/<pci bus id>
echo 1 > rom
cat rom > /tmp/vbios.rom
echo 0 > rom

[Ps (ps-mail)]

Created attachment 106353
lspci output for amilo

[Ps (ps-mail)]

Created attachment 106354
vbios from Amilo

[Ps (ps-mail)]

(In reply to comment #14)

This could be true. I can control it via /sys/class/backlight/acpi_video0/brightness. If I change /sys/class/backlight/radeon_bl0/brightness then the display is nearly black and cannot be restored.

After reboot the following values are set:
acpi_video0 = 7
radeon_bl0 = 0

I've attached a lspci -vvv to " lspci output for amilo" and the vbios to "vbios from Amilo"

[agd5f (agd5f)]

Can you attach the lspci -vnn output for your GPU?

[Ps (ps-mail)]

Created attachment 106410
lspci -vnn for Amilo

sure, here it is

[agd5f (agd5f)]

Created attachment 106441
patch 1/2

Do the attached patches help? The first patch adds a backlight module parameter to disable the gpu backlight device for testing. The second adds a quirk for the Amilo laptop.

[agd5f (agd5f)]

Created attachment 106442
patch 2/2

[Ps (ps-mail)]

Thanks for the patch, but I'm on vacation till 26th September, so long I cannot test it.

@Daniel
As you've got the same problem, could you test the patches?

[Daniel-kirsten-72 (daniel-kirsten-72)]

I can test the patches from 2014-09-17 on my amilo.

Can I apply them to the current fedora kernel code 3.14.18-100?

Should I apply both patches or test each patch separately?

Daniel

[agd5f (agd5f)]

Apply them both together.

[agd5f (agd5f)]

(In reply to comment #24)
> Apply them both together.

Well, assuming your laptop has the same pci ids as Patrick. If not, just append radeon.backlight=0 to the kernel command line in grub and attach your lspci -vnn output.

[Daniel-kirsten-72 (daniel-kirsten-72)]

(In reply to comment #25)

The pci-id of the VGA Controller is 01:00.0 for my Amilo.

However, I cannot apply the patches to the 3.14.18-100.fc19 kernel:

patch --dry-run -p1 < ~/software/0001-drm-radeon-add-a-module-parameter-for-backlight-cont.patch
checking file drivers/gpu/drm/radeon/radeon.h
Hunk #1 FAILED at 106.
1 out of 1 hunk FAILED
checking file drivers/gpu/drm/radeon/radeon_drv.c
Hunk #1 FAILED at 181.
Hunk #2 succeeded at 237 with fuzz 2 (offset -26 lines).
1 out of 2 hunks FAILED
checking file drivers/gpu/drm/radeon/radeon_encoders.c
Exit 1

patch --dry-run -p1 < ~/software/0002-drm-radeon-add-a-backlight-quirk-for-Amilo-Xi-2550.patch
checking file drivers/gpu/drm/radeon/radeon_encoders.c
Hunk #1 FAILED at 173.
1 out of 1 hunk FAILED
Exit 1

Which kernel should I use to test the patches?

Daniel

[agd5f (agd5f)]

They are written against 3.17.

[agd5f (agd5f)]

(In reply to comment #26)
> (In reply to comment #25)
>
> The pci-id of the VGA Controller is 01:00.0 for my Amilo.

That's the bus id. I need the output of lspci -vnn

[Daniel-kirsten-72 (daniel-kirsten-72)]

I tested the patches from 2014-09-17 against 3.17-rc5.

When I applied both patches, the backlight was not turned off, when the kernel switched into graphics mode.
The kernel worked very well.

Without the patches, the backlight was turned off, when the kernel switched into graphics mode.

Daniel

[Daniel-kirsten-72 (daniel-kirsten-72)]

Created attachment 106554
lspci -vnn for Daniel's amilo

[agd5f (agd5f)]

(In reply to comment #30)
> Created attachment 106554 [details]
> lspci -vnn for Daniel's amilo

You have the same configuration as Patrick.

(In reply to comment #29)
> I tested the patches from 2014-09-17 against 3.17-rc5.
>
> When I applied both patches, the backlight was not turned off, when the
> kernel switched into graphics mode.
> The kernel worked very well.

Great. I'll make sure the patches get upstream. Thanks for testing.

[Ps (ps-mail)]

I've just tested the patches on my notebook, too. Also here, the problem is fixed, with the patches you provided.

Do you already know, in which upstream versions, the fix will be published? 3.17? Or in an 3.16.x already?

[Dieter-nuetzel-hh (dieter-nuetzel-hh)]

They are in Linus 3.17 tree:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=005f800508eb391480f463dad3d54e5b4ec67d57

[Catalin (codreanu-catalin)]

I did some more testing and I nailed the change to the 3.15.7 kernel update.
I must have confused versions in my initial report.

Anyways, looking throught the changelog for that kernel version I found this changeset :

commit be907c8468c9f47882036109ba550cd2748b86a0
Author: Alex Deucher <email address hidden>
Date: Tue Jul 15 09:48:53 2014 -0400

    drm/radeon: set default bl level to something reasonable

    commit 201bb62402e0227375c655446ea04fcd0acf7287 upstream.

    If the value in the scratch register is 0, set it to the
    max level. This fixes an issue where the console fb blanking
    code calls back into the backlight driver on unblank and then
    sets the backlight level to 0 after the driver has already
    set the mode and enabled the backlight.

    bugs:
    https://bugs.freedesktop.org/show_bug.cgi?id=81382
    https://bugs.freedesktop.org/show_bug.cgi?id=70207

    Signed-off-by: Alex Deucher <email address hidden>
    Tested-by: David Heidelberger <email address hidden>
    Signed-off-by: Greg Kroah-Hartman <email address hidden>

This modified the way the radeon module handles default backlight values.
Looking through the first bug report I found out about the "radeon.backlight" kernel option.
Adding "radeon.backlight=0" to grub command line fixed the display brightness issue.

[penalvch (penalvch)]

Catalin, could you please test the latest upstream kernel available from the very top line at the top of the page (the release names are irrelevant for testing, and please do not test the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue.

If the test did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to 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 by clicking on the yellow circle with a black pencil icon, next to the word Tags, located at the bottom of the report description:
kernel-fixed-upstream
kernel-fixed-upstream-3.XY-rcZ

Where XY and Z are numbers corresponding to the kernel version.

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-3.XY-rcZ

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.

[Mig+freedesktop (mig+freedesktop)]

Hi, it took me quite some time to get here, but hopefully you can still solve my problem.
I'm running a 2006 Intel iMac (Core Duo) under Unbuntu 12.04LTS server, which sits on my desk and almost never log to the console, which would normally go blank a few minutes after boot.

There is strong evidence that this patch found its way to my "stock" kernel back in september 2014, and since then my iMac exhibits the following behaviour after boot:
- whenever the console blanking activates, backlight goes to MAX (with my LCD screen going all strange and overheating — even causing fans to blow)
- only way out is to echo 0 > /sys/class/backlight/radeon_bl0/brightness — which I 'crontabbed' but is not exactly satisfactory.
- any other value causes the backlight to go all the way up and overheat.

I did try to "echo 1 > /sys/class/backlight/acpi_video0/brightness" today, and that caused the iMac to reboot.

I have not experimented anything else, but would be happy to help.

uname is "Linux xxx 3.13.0-49-generic #81~precise1-Ubuntu SMP Wed Mar 25 16:32:40 UTC 2015 i686 i686 i386 GNU/Linux"

[Mig+freedesktop (mig+freedesktop)]

Created attachment 115253
lspci -vnn for Christophe's iMac

[Alexdeucher (alexdeucher)]

Should be fixed in this patch:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b7bc596ebbe0cddc97d76ef9309f64471bbf13eb

[Mig+freedesktop (mig+freedesktop)]

Apparently only "set the default backlight level to something reasonable" patch was applied to 3.13, so I don't have the "radeon_encoder_add_backlight" function, thus this won't work at all.

Would you suggest I first apply the patch published here on 2014-09-17?

[Mig+freedesktop (mig+freedesktop)]

Well, I did, '2014-09-17 15:38 UTC' and '2014-09-17 15:39 UTC' patches apply ok and it works. Sorry for the inconvenience.
(perhaps one should consider pushing these two upstream instead of the fist one?)...

[Alexdeucher (alexdeucher)]

(In reply to Christophe Migliorini from comment #38)
> Well, I did, '2014-09-17 15:38 UTC' and '2014-09-17 15:39 UTC' patches apply
> ok and it works. Sorry for the inconvenience.
> (perhaps one should consider pushing these two upstream instead of the fist
> one?)...

Those patches are upstream as well.

[Alexdeucher (alexdeucher)]

(In reply to Alex Deucher from comment #39)
> (In reply to Christophe Migliorini from comment #38)
> > Well, I did, '2014-09-17 15:38 UTC' and '2014-09-17 15:39 UTC' patches apply
> > ok and it works. Sorry for the inconvenience.
> > (perhaps one should consider pushing these two upstream instead of the fist
> > one?)...
>
> Those patches are upstream as well.

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bc13018b5eba26ca229b33763c9e61fac31a1925
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8aff6ad5a393b8e2ad00dce4d278ecf41397bf0d

[Mig+freedesktop (mig+freedesktop)]

Good. Hopefully into 12.04LTS before it's no longer supported :-).