Backlight does not change when adjust it higher than 50% after S3

Bug #1625932 reported by AceLan Kao on 2016-09-21
This bug affects 2 people
Affects Status Importance Assigned to Milestone
HWE Next
AceLan Kao
linux (Ubuntu)
AceLan Kao
Nominated for Vivid by Anthony Wong

Bug Description

Backlight does not change when adjust it higher than 50% after S3

1. Install ubuntu 16.04 and boot into OS
2. suspend system
3. resume system from S3
4. Try to adjust brightness level

Expected results: Backlight should be changed when adjust it

Actual results: Backlight does not change when adjust it higher than 50% after S3

CVE References

AceLan Kao (acelankao) wrote :

The upstream bug

And the issue could be fixed by the following 2 commits in drm-intel-next-queued.

commit 32b421e79e6b546da1d469f1229403ac9142d695
Author: Jani Nikula <email address hidden>
Date: Mon Sep 19 13:35:25 2016 +0300

    drm/i915/backlight: setup and cache pwm alternate increment value


commit e29aff05f239f8dd24e9ee7816fd96726e20105a
Author: Shawn Lee <email address hidden>
Date: Mon Sep 19 13:35:26 2016 +0300

    drm/i915/backlight: setup backlight pwm alternate increment on backlight enable

Changed in linux (Ubuntu):
status: New → In Progress
AceLan Kao (acelankao) on 2016-09-21
tags: added: originate-from-1620993 somerville
Changed in linux (Ubuntu Xenial):
status: New → Fix Committed
Andy Whitcroft (apw) on 2016-09-23
Changed in linux (Ubuntu):
importance: Undecided → High
Changed in linux (Ubuntu Xenial):
importance: Undecided → High
Brad Figg (brad-figg) wrote :

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-xenial' to 'verification-done-xenial'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See for documentation how to enable and use -proposed. Thank you!

tags: added: verification-needed-xenial
Changed in hwe-next:
status: New → Fix Committed
Changed in linux (Ubuntu):
status: In Progress → Fix Committed
Joseph Salisbury (jsalisbury) wrote :


When you have a chance, can you verify this bug is fixed? See comment #2.

Thanks in advance!

tags: added: verification-done-xenial
removed: verification-needed-xenial
Launchpad Janitor (janitor) wrote :
Download full text (17.5 KiB)

This bug was fixed in the package linux - 4.4.0-42.62

linux (4.4.0-42.62) xenial; urgency=low

  * Fix GRO recursion overflow for tunneling protocols (LP: #1631287)
    - tunnels: Don't apply GRO to multiple layers of encapsulation.
    - gro: Allow tunnel stacking in the case of FOU/GUE

  * CVE-2016-7039
    - SAUCE: net: add recursion limit to GRO

linux (4.4.0-41.61) xenial; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1628204

  * nvme drive probe failure (LP: #1626894)
    - (fix) NVMe: Don't unmap controller registers on reset

linux (4.4.0-40.60) xenial; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1627074

  * Permission denied in CIFS with kernel 4.4.0-38 (LP: #1626112)
    - Fix memory leaks in cifs_do_mount()
    - Compare prepaths when comparing superblocks
    - SAUCE: Fix regression which breaks DFS mounting

  * Backlight does not change when adjust it higher than 50% after S3
    (LP: #1625932)
    - SAUCE: i915_bpo: drm/i915/backlight: setup and cache pwm alternate
      increment value
    - SAUCE: i915_bpo: drm/i915/backlight: setup backlight pwm alternate
      increment on backlight enable

linux (4.4.0-39.59) xenial; urgency=low

  [ Joseph Salisbury ]

  * Release Tracking Bug
    - LP: #1625303

  * thunder: chip errata w/ multiple CQEs for a TSO packet (LP: #1624569)
    - net: thunderx: Fix for issues with multiple CQEs posted for a TSO packet

  * thunder: faulty TSO padding (LP: #1623627)
    - net: thunderx: Fix for HW issue while padding TSO packet

  * CVE-2016-6828
    - tcp: fix use after free in tcp_xmit_retransmit_queue()

  * Sennheiser Officerunner - cannot get freq at ep 0x83 (LP: #1622763)
    - SAUCE: (no-up) ALSA: usb-audio: Add quirk for sennheiser officerunner

  * Backport E3 Skylake Support in ie31200_edac to Xenial (LP: #1619766)
    - EDAC, ie31200_edac: Add Skylake support

  * Ubuntu 16.04 - Full EEH Recovery Support for NVMe devices (LP: #1602724)
    - SAUCE: nvme: Don't suspend admin queue that wasn't created

  * ISST-LTE:pNV: system ben is hung during ST (nvme) (LP: #1620317)
    - blk-mq: Allow timeouts to run while queue is freezing
    - blk-mq: improve warning for running a queue on the wrong CPU
    - blk-mq: don't overwrite rq->mq_ctx

  * lsattr 32bit does not work on 64bit kernel (Inappropriate ioctl error)
    (LP: #1619918)
    - btrfs: bugfix: handle FS_IOC32_{GETFLAGS, SETFLAGS, GETVERSION} in

  * radeon: monitor connected to onboard VGA doesn't work with Xenial
    (LP: #1600092)
    - drm/radeon/dp: add back special handling for NUTMEG

  * initramfs includes qle driver, but not firmware (LP: #1623187)
    - qed: add MODULE_FIRMWARE()

  * [Hyper-V] Rebase Hyper-V to 4.7.2 (stable) (LP: #1616677)
    - hv_netvsc: Implement support for VF drivers on Hyper-V
    - hv_netvsc: Fix the list processing for network change event
    - Drivers: hv: vmbus: Introduce functions for estimating room in the ring
    - Drivers: hv: vmbus: Use READ_ONCE() to read variables that are volatile
    - Drivers: hv: vmbus: Export the vmbus_set_event() API
    - lcoking/barriers, arch: Use smp barriers...

Changed in linux (Ubuntu Xenial):
status: Fix Committed → Fix Released
AceLan Kao (acelankao) on 2016-10-12
Changed in linux (Ubuntu):
status: Fix Committed → Fix Released
Changed in hwe-next:
status: Fix Committed → Fix Released
perry_yuan (perry-yuan) wrote :

Could i know whether the two patches have been merged into Ubuntu 14.04 kernel codes ?
I found that the issue still can be reproduced on Ubuntu 3.19.0-78 kernel .

AceLan Kao (acelankao) wrote :

Perry, yes, I'm still working on this to backport the patches to 3.19 kernel.
But, I can not successfully reproduce this issue on the machines I have.
Could you help to try if the kernel fix the issue?

The kernel is a little bit older than the latest one,
so please make sure to boot the system with the right kernel.

AceLan Kao (acelankao) wrote :

Found another machine and restored the factory image, but still can't reproduce this issue.

To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.