regression: backlight can't be adjusted on UX32VD with 3.19.0-12-generic kernel

Bug #1440270 reported by Matthew Haughton on 2015-04-04
This bug affects 2 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Timo Aaltonen
Timo Aaltonen

Bug Description

The keyboard buttons are working as I get the on screen notification. But it has no effect on the backlight itself.

I rebooted and switched back to 3.19.0-11-generic which works fine, rebooted and went back to 3.19.0-12-generic and it stopped working again, so very confident something broke in the new kernel version.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-12-generic 3.19.0-12.12
ProcVersionSignature: Ubuntu 3.19.0-12.12-generic 3.19.3
Uname: Linux 3.19.0-12-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.17-0ubuntu1
Architecture: amd64
 /dev/snd/controlC0: snafu109 2549 F.... pulseaudio
CurrentDesktop: XFCE
Date: Fri Apr 3 21:34:50 2015
HibernationDevice: RESUME=UUID=4e46a15c-d441-4b34-ae15-a93302da75a5
InstallationDate: Installed on 2012-12-26 (828 days ago)
InstallationMedia: Xubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120817.3)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-12-generic root=UUID=687d7b6d-6fe2-413c-84c1-ed511edff5f9 ro quiet splash vt.handoff=7
 linux-restricted-modules-3.19.0-12-generic N/A
 linux-backports-modules-3.19.0-12-generic N/A
 linux-firmware 1.143
SourcePackage: linux
UpgradeStatus: Upgraded to vivid on 2015-03-10 (24 days ago) 01/29/2013
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: UX32VD.214
dmi.board.asset.tag: ATN12345678901234567 UX32VD
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrUX32VD.214:bd01/29/2013:svnASUSTeKCOMPUTERINC.:pnUX32VD:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX32VD:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0: UX32VD
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

CVE References

Matthew Haughton (snafu109) wrote :

This change was made by a bot.

Changed in linux (Ubuntu):
status: New → Confirmed

Matthew Haughton, thank you for reporting this and helping make Ubuntu better. 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 ? 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:

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:

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.

tags: added: latest-bios-214 regression-update
Changed in linux (Ubuntu):
importance: Undecided → Low
status: Confirmed → Incomplete
tags: added: performing-bisect
Changed in linux (Ubuntu):
status: Incomplete → In Progress
importance: Low → Medium
assignee: nobody → Joseph Salisbury (jsalisbury)
Marco Cè (marco89-7) wrote :

I have the same issue on a Dell XPS 13 (L322X, Ivy Bridge model with 1080p display).
- With 3.19.0-11-generic backlight is working fine.
- With 3.19.0-12-generic, keyboard buttons produce notifications but the brightness is not changed. I can manually change it writing to '/sys/class/backlight/intel_backlight/brightness'.
- I tested 4.0.0-040000rc7-generic from kernel-ppa/mainline and it is working fine, as 3.19.0-11-generic.
With all kernels, when brightness is set to 0 the display (not only backlight) turn off, but I think it's another bug.

I'm available if more tests are needed to bisect the issue.

tags: added: kernel-fixed-upstream kernel-fixed-upstream-3.19.0-11-generic
tags: added: kernel-fixed-upstream-4.0.0-040000rc7
removed: kernel-fixed-upstream-3.19.0-11-generic
Joseph Salisbury (jsalisbury) wrote :

Can folks affected by this bug please test the v4.0-rc1 kernel:

tags: added: kernel-key
Changed in linux (Ubuntu Vivid):
assignee: Joseph Salisbury (jsalisbury) → nobody
status: In Progress → Confirmed
importance: Medium → High
Changed in linux (Ubuntu Vivid):
status: Confirmed → Triaged
Changed in linux (Ubuntu Vivid):
assignee: nobody → Joseph Salisbury (jsalisbury)
Matthew Haughton (snafu109) wrote :

I just booted into 4.0-rc1. Backlight controls work again.

tags: added: kernel-fixed-upstream-4.0-rc1
tags: added: needs-reverse-bisect
removed: kernel-fixed-upstream-4.0.0-040000rc7
Marco Cè (marco89-7) wrote :

I confirm that backlight controls work both with 4.0-rc1 and 3.19.0-997.
However, with 3.19.0-997 the external usb mouse moves the pointer on the screen with a lag of the order of one second, being unusable. Probably this is unrelated.

Timo Aaltonen (tjaalton) wrote :

Thanks for testing. Yes the slow mouse is unrelated, fixed later in 4.0.

Timo Aaltonen (tjaalton) wrote :

the offending commit has been identified and will be reverted from 3.19.0-13

Changed in linux (Ubuntu Vivid):
status: Triaged → In Progress
Changed in linux (Ubuntu Vivid):
assignee: Joseph Salisbury (jsalisbury) → Timo Aaltonen (tjaalton)
Launchpad Janitor (janitor) wrote :
Download full text (4.2 KiB)

This bug was fixed in the package linux - 3.19.0-13.13

linux (3.19.0-13.13) vivid; urgency=low

  [ Andy Whitcroft ]

  * [Packaging] initscripts need installing when making the package
  * [Packaging] initscripts work around bug in debhelper systemd support

  [ Jay Vosburgh ]

  * SAUCE: fan: Proof of concept implementation
    - LP: #1439706

  [ Leann Ogasawara ]

  * Release Tracking Bug
    - LP: #1442165

  [ Upstream Kernel Changes ]

  * Revert "drm: fix mismerge in drm_crtc.c"
    - LP: #1440270, #1440392
  * e1000e: initial support for i219
    - LP: #1400955
  * e1000e: fix obscure comments
    - LP: #1400955
  * e1000e: remove calls to ioremap/unmap for NVM addr
    - LP: #1400955
  * d-i: Enable usb modules on arm64
  * drm/amdkfd: Initialize only amdkfd's assigned pipelines
  * storvsc: use cmd_size to allocate per-command data
  * storvsc: in responce to a scan event, scan the host
  * storvsc: force discovery of LUNs that may have been removed.
  * storvsc: fix a bug in storvsc limits
  * Drivers: hv: vmbus: Use get_cpu() to get the current CPU
  * Tools: hv: address compiler warnings for hv_fcopy_daemon.c
  * Tools: hv: do not add redundant '/' in hv_start_fcopy()
  * Drivers: hv: hv_balloon: Make adjustments in computing the floor
  * Drivers: hv: hv_balloon: Fix a locking bug in the balloon driver
  * Drivers: hv: hv_balloon: Don't post pressure status from interrupt
  * Drivers: hv: vmbus: Implement a clockevent device
  * Drivers: hv: vmbus: Fix a bug in vmbus_establish_gpadl()
  * Drivers: hv: vmbus: Support a vmbus API for efficiently sending page
  * hv: hv_fcopy: drop the obsolete message on transfer failure
  * Drivers: hv: check vmbus_device_create() return value in
  * Drivers: hv: rename sc_lock to the more generic lock
  * Drivers: hv: vmbus: serialize Offer and Rescind offer
  * Drivers: hv: vmbus: hv_process_timer_expiration() can be static
  * hyperv: netvsc.c: match wait_for_completion_timeout return type
  * hyperv: fix sparse warnings
  * powerpc/powernv: Add OPAL soft-poweroff routine
    - LP: #1439562
  * drivers/sbus/char/envctrl.c: ignore orderly_poweroff return value
    - LP: #1439562
  * kernel/reboot.c: add orderly_reboot for graceful reboot
    - LP: #1439562
  * powerpc/powernv: reboot when requested by firmware
    - LP: #1439562
  * powerpc/kernel: Make syscall_exit a local label
    - LP: #1439562
  * powerpc: Remove old compile time disabled syscall tracing code
    - LP: #1439562
  * powerpc: Add a proper syscall for switching endianness
    - LP: #1439562
  * powerpc/powernv: Remove "opal" prefix from pr_xxx()s
    - LP: #1439562
  * powerpc/powernv: Separate function for OPAL IRQ setup
    - LP: #1439562
  * powerpc/powernv: Add OPAL message notifier unregister function
    - LP: #1439562
  * powerpc/powernv: Support OPAL requested heartbeat
    - LP: #1439562
  * device: Add dev_of_node() accessor
    - LP: #1439562
  * drivers/core/of: Add symlink to device-tree from devices with an OF
    - LP: #1439562
  * ipv6: Don't reduce hop limit for an interface
    - LP: #1441103
    - CVE-2015-2922
  * x86/microcode/int...


Changed in linux (Ubuntu Vivid):
status: In Progress → Fix Released
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