Backlight control does not work, but there are entries in /sys/class/backlight. Lenovo B570

[.....]

Laptop model: Lenovo B570
package version: Ubuntu 3.13.0-32.57-generic 3.13.11.4

I expected the keys for changeing the backlight brightness to work
they had no effect on the backlight

further details in attatched Tar

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-32-generic 3.13.0-32.57
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic i686
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: x321x321 1977 F.... pulseaudio
Date: Sat Aug 9 16:11:34 2014
HibernationDevice: RESUME=UUID=61c2c6a6-4b45-4af0-941a-dadf05ad0aba
InstallationDate: Installed on 2014-07-31 (8 days ago)
InstallationMedia: Xubuntu 14.04.1 LTS "Trusty Tahr" - Release i386 (20140723)
MachineType: LENOVO 1068FJG
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-32-generic root=/dev/mapper/xubuntu--vg-root ro quiet splash vt.handoff=7
PulseList:
 Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
 No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-32-generic N/A
 linux-backports-modules-3.13.0-32-generic N/A
 linux-firmware 1.127.5
SourcePackage: linux
StagingDrivers: rts5139
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/11/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 44CN36WW
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Emerald Lake
dmi.board.vendor: LENOVO
dmi.board.version: FAB1
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnLENOVO:bvr44CN36WW:bd07/11/2011:svnLENOVO:pn1068FJG:pvrLenovoB570:rvnLENOVO:rnEmeraldLake:rvrFAB1:cvnLENOVO:ct10:cvr0.1:
dmi.product.name: 1068FJG
dmi.product.version: Lenovo B570
dmi.sys.vendor: LENOVO

[..... (a..-deactivatedaccount)]

ignore comment about the tar

[..... (a..-deactivatedaccount)]

Workaround information

Reboot with only the kernel parameter acpi_backlight=vendor :
no change

output of ls /sys/class/backlight

ideapad
intel_backlight
thinkpad_screen

output of ls -la /sys/class/backlight/intel_backlight/ > lslabacklight as root

total 0
drwxr-xr-x 3 root root 0 Aug 8 23:17 .
drwxr-xr-x 4 root root 0 Aug 8 23:17 ..
-r--r--r-- 1 root root 4096 Aug 8 23:27 actual_brightness
-rw-r--r-- 1 root root 4096 Aug 8 23:27 bl_power
-rw-r--r-- 1 root root 4096 Aug 8 23:17 brightness
lrwxrwxrwx 1 root root 0 Aug 8 23:27 device -> ../../card0-LVDS-1
-r--r--r-- 1 root root 4096 Aug 8 23:17 max_brightness
drwxr-xr-x 2 root root 0 Aug 8 23:27 power
lrwxrwxrwx 1 root root 0 Aug 8 23:27 subsystem -> ../../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Aug 8 23:17 type
-rw-r--r-- 1 root root 4096 Aug 8 23:17 uevent

echo 8 > /sys/class/backlight/intel_backlight/brightness
brightness changes

reboot with just kernel parameter video.use_native_backlight=1

keys still cannot be used for changing brightness

creating a new file in /usr/share/X11/xorg.conf.d/80-backlight.conf and paste into it the following code:

Section "Device"
    Identifier "Intel Graphics"
    Driver "intel"
    Option "AccelMethod" "sna"
    Option "Backlight" "intel_backlight" # use your backlight that works here
    BusID "PCI:0:2:0"
EndSection

keys can now be used for changing brightness of backlight

[Brad Figg (brad-figg)]

This change was made by a bot.

[..... (a..-deactivatedaccount)]

using mainline kernel builds verified that bug appears first in linux 3.10.0-031000rc1

http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.10-rc1-saucy/linux-image-3.10.0-031000rc1-generic_3.10.0-031000rc1.201305130510_i386.deb

[..... (a..-deactivatedaccount)]

last works in the 3.9.x kernels

[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 v3.17 kernel[0].

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/v3.17-rc1-utopic/

[..... (a..-deactivatedaccount)]

I am unable to test Linux v3.17-rc2 located at http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.17-rc2-utopic/
as it fails to boot.
Will reattempt on next version and report results

[..... (a..-deactivatedaccount)]

Tested Linux v3.17-rc3 http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.17-rc3-utopic/ confirmed bug exists in 3.17-rc3

[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.

Once this bug is reported upstream, please add the tag: 'kernel-bug-reported-upstream'.

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

[Joseph Salisbury (jsalisbury)]

We can also perform a kernel bisect to identify the commit that introduced this regression in 3.10. Would you be able to test 7 - 10 kernel for the bisect process?

[..... (a..-deactivatedaccount)]

tested listed kernels
non listed kernels are ones that where unbootable

3.7.0-030700-generic backlight not yet working
3.7.0-030700rc6-generic backlight not yet working

3.8.9-030809-generic backlight working
3.8.10-030810-generic backlight working
3.8.11-030811-generic backlight working
3.8.12-030812-generic backlight working
3.8.13-030813-generic backlight working
3.8.13-03081301-generic backlight working
3.8.13-03081302-generic backlight working
3.8.13-03081303-generic backlight working
3.8.13-03081304-generic backlight working
3.8.13-03081305-generic backlight working
3.8.13-03081306-generic backlight working
3.8.13-03081307-generic backlight working
3.8.13-03081308-generic backlight working
3.8.13-03081309-generic backlight working
3.8.13-03081310-generic backlight working
3.8.13-03081311-generic backlight working
3.8.13-03081312-generic backlight working
3.8.13-03081313-generic backlight working
3.8.13-03081314-generic backlight working
3.8.13-03081315-generic backlight working
3.8.13-03081316-generic backlight working
3.8.13-03081317-generic backlight working
3.8.13-03081318-generic backlight working
3.8.13-03081319-generic backlight working
3.8.13-03081320-generic backlight working
3.8.13-03081321-generic backlight working
3.8.13-03081322-generic backlight working
3.8.13-03081323-generic backlight working
3.8.13-03081324-generic backlight working
3.8.13-03081325-generic backlight working
3.8.13-03081326-generic backlight working
3.8.13-03081327-generic backlight working
3.8.13-03081328-generic backlight working

3.9.0-030900-generic backlight backlight working
3.9.0-030900rc7-generic backlight backlight working
3.9.0-030900rc8-generic backlight backlight working
3.9.1-030901-generic backlight backlight working
3.9.2-030902-generic backlight backlight working
3.9.3-030903-generic backlight backlight working
3.9.4-030904-generic backlight backlight working
3.9.5-030905-generic backlight backlight working
3.9.6-030906-generic backlight backlight working
3.9.7-030907-generic backlight backlight working
3.9.8-030908-generic backlight backlight working
3.9.9-030909-generic backlight backlight working
3.9.10-030910-generic backlight backlight working
3.9.11-030911-generic backlight backlight working

3.10.0-031000rc1-generic backlight doesn’t work
3.10.0-031000rc2-generic backlight doesn’t work
3.10.0-031000rc3-generic backlight doesn’t work
3.10.0-031000rc4-generic backlight doesn’t work
3.10.0-031000rc5-generic backlight doesn’t work
3.10.0-031000rc6-generic backlight doesn’t work
3.10.0-031000rc7-generic backlight doesn’t work
3.10.0-031000-generic backlight doesn’t work

[Joseph Salisbury (jsalisbury)]

I started a kernel bisect between v3.9 final and v3.10-rc1. The kernel bisect will require testing of about 10 - 12 test kernels.

I built the first test kernel, up to the following commit:
73287a43cc79ca06629a88d1a199cd283f42456a

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

i can confirm that the bug appears in your kernel

thanks

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
5d434fcb255dec99189f1c58a06e4f56e12bf77d

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is not present in latest kernel

http://kernel.ubuntu.com/~jsalisbury/lp1354710

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
91bc033c4d01656e3d8e45a13fd58924a3099693

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

cannot test latest kernel as my machine requires i386 and only amd64 kernel is avalible
thanks

[Joseph Salisbury (jsalisbury)]

I skipped the last commit since it would not build i386, and built the next test kernel, up to the following commit:
b2a63431b49f4ef4df1ea5ddb799af48cfa349fc

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

the bug is not present in your latest kernel

[..... (a..-deactivatedaccount)]

could you do a batch of test kernels if possible

thanks

[Joseph Salisbury (jsalisbury)]

I can't build a bunch of test kernels because it requires the testing result for the last kernel before the next kernel is built.

I built the next test kernel, up to the following commit:
4294dcf7e335da72fe81538c46b4a8e83037ea20

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
078be02b80359a541928c899c2631f39628f56df

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug exists in your latest build

[..... (a..-deactivatedaccount)]

sorry tested wrong kernel ignore last comment

bug is not present in latest build

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
5c574f501d46be79a4a1344b63747844be3674f5

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
149b306089b88e186942a8d6647028ae6683aaf9

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

the bug is present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
151173e8ce9b95bbbbd7eedb9035cfaffbdb7cb2

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
371deb9500831ad1afbf9ea00e373f650deaed2f

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
554c06ba3ee29cf453fca17e9e61120b75aa476d

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
e4f5a3adc454745fea35f1c312e14cbeba6e0ea4

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is presentin your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
0acaab5367a2c4140bd965a0ad3ea265af4d43ed

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
0ad4991cae47c0d3ae93e1531ba5572d223d700c

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
94a409319561ec1847fd9bf996a2d5843ad00932

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
a50188dae3089dcd15a6ae793528c157680891f1

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug is present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
0fa8794e65348a08722aa3eed9df0034bca8d4cb

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
34f8f1031cdccc73ab002dfe5f65ec89c3314457

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[Joseph Salisbury (jsalisbury)]

Actually there seems to be some network error at the moment. I'll post the kernel shortly.

[Joseph Salisbury (jsalisbury)]

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[..... (a..-deactivatedaccount)]

bug not present in your latest kernel

[Joseph Salisbury (jsalisbury)]

The bisect reported the following as the first bad commit:

commit a50188dae3089dcd15a6ae793528c157680891f1
Author: Aaron Lu <email address hidden>
Date: Mon Apr 22 14:08:32 2013 +0200

    acpi: video: enhance the quirk detect logic of _BQC

I built a Trusty test kernel with that commit reverted. Can you test this kernel and see if it resolves this bug? It can be downloaded from:

http://kernel.ubuntu.com/~jsalisbury/lp1354710

[..... (a..-deactivatedaccount)]

bug still present

not sure why though

if you have previous kernel builds i can retest just in case

thanks

[Joseph Salisbury (jsalisbury)]

Did you install both the linux-image and linux-image-extra .deb packages?

[..... (a..-deactivatedaccount)]

in this case i definately have though it is possible i failed to install the linux extra package somewhere along the way

apolagies for this

as i stated previously i would be happy to retest all your previous kernel builds if you still have them

[Joseph Salisbury (jsalisbury)]

I'll look at all the bisect results and see if this commit can be reverted in mainline for testing.

Can you test the latest mainline kernel, just to confirm another commit does not fix this? It can be downloaded from:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.17-rc7-utopic/

[..... (a..-deactivatedaccount)]

confirmed bug exists in latest maineline kernel

[Joseph Salisbury (jsalisbury)]

I built the mainline kernel with commit a50188d reverted. Can you test this kernel and see if it resolves this bug? It can be downloaded from:

http://kernel.ubuntu.com/~jsalisbury/lp1354710

[..... (a..-deactivatedaccount)]

bug present in latest kernel

[Joseph Salisbury (jsalisbury)]

That implies that commit a50188dae3089dcd15a6ae793528c157680891f1 is not what introduced this bug. We may want to go through the bisect results again. Maybe one of the kernel was really good or bad and we marked it incorrect.

[..... (a..-deactivatedaccount)]

can you upload a tar.xz of all the kernels you built previously?

I can test them again to confirm which are affected.

thanks

[Joseph Salisbury (jsalisbury)]

I copied all of the test kernels back to:
http://kernel.ubuntu.com/~jsalisbury/lp1354710

There is a directory for each SHA1 tested. There is also a file there named bisect.log, which list the kernels were marked as good and bad.

[..... (a..-deactivatedaccount)]

could you recheck the kernels are in the right folders as

there are no test kernels in a50188dae3089dcd15a6ae793528c157680891f1 when there should be one (according to the bisect log)

and there are two sets in 94a409319561ec1847fd9bf996a2d5843ad00932

so I am unsure if the folders the kernels are in reflect the commits accurately

will test once clarified

thanks

[Joseph Salisbury (jsalisbury)]

I'll rebuild the kernels for both a50188dae3089dcd15a6ae793528c157680891f1 and 94a409319561ec1847fd9bf996a2d5843ad00932 and re-upload them. Just let me know if any other kernels are missing from the sub-directories and I can rebuild them as well. I may not have made copies of them when I first built them.

[..... (a..-deactivatedaccount)]

0acaab5367a2c4140bd965a0ad3ea265af4d43ed BUG PRESENT
0ad4991cae47c0d3ae93e1531ba5572d223d700c BUG NOT PRESENT
Test results

0fa8794e65348a08722aa3eed9df0034bca8d4cb BUG NOT PRESENT
5c574f501d46be79a4a1344b63747844be3674f5 BUG NOT PRESENT
5d434fcb255dec99189f1c58a06e4f56e12bf77d BUG NOT PRESENT
34f8f1031cdccc73ab002dfe5f65ec89c3314457 BUG NOT PRESENT
078be02b80359a541928c899c2631f39628f56df BUG NOT PRESENT
149b306089b88e186942a8d6647028ae6683aaf9 BUG PRESENT
371deb9500831ad1afbf9ea00e373f650deaed2f BUG PRESENT
554c06ba3ee29cf453fca17e9e61120b75aa476d BUG NOT PRESENT
4294dcf7e335da72fe81538c46b4a8e83037ea20 BUG NOT PRESENT
73287a43cc79ca06629a88d1a199cd283f42456a BUG PRESENT
151173e8ce9b95bbbbd7eedb9035cfaffbdb7cb2 BUG NOT PRESENT
a50188dae3089dcd15a6ae793528c157680891f1 BUG PRESENT
b2a63431b49f4ef4df1ea5ddb799af48cfa349fc BUG NOT PRESENT
e4f5a3adc454745fea35f1c312e14cbeba6e0ea4 BUG PRESENT

94a409319561ec1847fd9bf996a2d5843ad00932 needs kernel for testing

[..... (a..-deactivatedaccount)]

other than 94a409319561ec1847fd9bf996a2d5843ad00932 which is not yet up and so not tested
evrything is the same

[Joseph Salisbury (jsalisbury)]

I copied the kernels up to commit:
94a409319561ec1847fd9bf996a2d5843ad00932

back up to the server.

[..... (a..-deactivatedaccount)]

94a409319561ec1847fd9bf996a2d5843ad00932 BUG PRESENT

so the results are the exactly the same as the last bisect

[..... (a..-deactivatedaccount)]

could there be multiple buggy comits ? and if so could you try reverting all the commits marked as bad
then working bakwards ?