on thinkpad-acpi devices, brightness setting ommits most steps

[ari]

Brightness changes in very rough steps on some Machines, but only when there is the gpm-OSD appearing showing the brightness setting. So the bug appears not when the session showed is locked, but in an active session or on the login screen the bug appears.

On my machine (thinkpad X60) brightness changes with two steps between min and max - these steps are different depending on wether you go up or down hough. So you can hit 6 settings. I think the firmware is capable I think 8, surely indepent on wether set higher or lower.

This is found on an X60 Tablet, an Lenovo Netbook (sorry, not sure which device exactly) and an X201 Tablet. This leads me to believe this is an issue with the thinkpad-acpi kernel module, which has an proprietary interface for the screen brightness.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: gnome-power-manager 2.32.0-2ubuntu2
ProcVersionSignature: Ubuntu 3.0-1.2-generic 3.0.0-rc3
Uname: Linux 3.0-1-generic x86_64
Architecture: amd64
Date: Sun Sep 4 21:28:58 2011
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GnomeSessionSuspendInhibited: No
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
MachineType: LENOVO 6363C7G
ProcEnviron:
 LANGUAGE=de_CH:en
 LANG=de_CH.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: root=/dev/hostname/ubuntu ro splash quiet cryptopts=source=UUID=fc6bed20-d029-418d-82ca-cf4b932bb6c5,target=hostname-crypt,lvm=hostname-ubuntu loop.max_part=63
SourcePackage: gnome-power-manager
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/23/2008
dmi.bios.vendor: LENOVO
dmi.bios.version: 7JET27WW (1.12 )
dmi.board.name: 6363C7G
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7JET27WW(1.12):bd01/23/2008:svnLENOVO:pn6363C7G:pvrThinkPadX60Tablet:rvnLENOVO:rn6363C7G:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 6363C7G
dmi.product.version: ThinkPad X60 Tablet
dmi.sys.vendor: LENOVO

[pisix (vv-40in)]

Agree this is a bug, the problem is exactly the same on my IBM T60 2623-D6U, Ubuntu 12.04. It is possible to have "single step" brightness using 1) kernel parameter acpi_backlight=vendor and 2) thinkpad_acpi module parameter brightness_enable=0. But in this case OSD brighness change notification desappears.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[linrunner (linrunner)]

I'm affected too: ThinkPad X200 and X220 w/ Ubuntu 12.04.

In fact this is a kernel bug and there already is a patch in mainline: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ff413195e830541afeae469fc866ecd0319abd7e

I can confirm that the patch works for me an some more Thinkpad users when applied to the current Precise kernel 3.2.0-27.43 and I *strongly* suggest to integrate this patch in the Precise kernel.

Kernel packages including this patch can be found in my PPA: https://launchpad.net/~linrunner/+archive/thinkpad-extras

[Joseph Salisbury (jsalisbury)]

This bug was filed against a series that is no longer supported and so is being marked as Won't Fix. If this issue still exists in a supported series, please file a new bug.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Luis Henriques (henrix)]

This bug is awaiting verification that the kernel for Precise in -proposed solves the problem (3.2.0-35.55). Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-precise' to 'verification-done-precise'.

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

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Luis Henriques (henrix)]

Anthony (or someelse with this issue), could you please verify this bug for Precise, as per comment #6? Thanks.

[Luis Henriques (henrix)]

I'm tagging this as verified, as the fix is a oneliner and its available in mainline kernels.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.2.0-35.55

---------------
linux (3.2.0-35.55) precise-proposed; urgency=low

  [Luis Henriques]

  * Release Tracking Bug
    - LP: #1086856

  [ Andy Whitcroft ]

  * Revert "SAUCE: ata_piix: add a disable_driver option"
    - LP: #1079084
  * Revert "SAUCE: ata_piix: defer disks to the Hyper-V drivers by default"
    - LP: #1079084
  * SAUCE: ata_piix: add a disable_driver option
    - LP: #1079084, #994870

  [ Upstream Kernel Changes ]

  * libata: add a host flag to ignore detected ATA devices
    - LP: #1079084
  * ata_piix: defer disks to the Hyper-V drivers by default
    - LP: #1079084, #929545, #942316

linux (3.2.0-35.54) precise-proposed; urgency=low

  [Luis Henriques]

  * Release Tracking Bug
    - LP: #1086349

  [ Kees Cook ]

  * Revert "SAUCE: SECCOMP: audit: always report seccomp violations"
    - LP: #1079469

  [ Luis Henriques ]

  * SAUCE: SECCOMP: audit: fix build on archs without CONFIG_AUDITSYSCALL
    - LP: #1079469

  [ Upstream Kernel Changes ]

  * seccomp: forcing auditing of kill condition
    - LP: #1079469
  * Bluetooth: Avoid calling undefined smp_conn_security()
    - LP: #1081676
  * x86: Remove the ancient and deprecated disable_hlt() and enable_hlt()
    facility
    - LP: #1081676
  * drm/nouveau: silence modesetting spam on pre-gf8 chipsets
    - LP: #1081676
  * drm/nouveau: fix suspend/resume when in headless mode
    - LP: #1081676
  * drm/nouveau: headless mode by default if pci class != vga display
    - LP: #1081676
  * nfsd: add get_uint for u32's
    - LP: #1081676
  * ALSA: PCM: Fix some races at disconnection
    - LP: #1081676
  * ALSA: usb-audio: Fix races at disconnection
    - LP: #1081676
  * ALSA: usb-audio: Use rwsem for disconnect protection
    - LP: #1081676
  * ALSA: usb-audio: Fix races at disconnection in mixer_quirks.c
    - LP: #1081676
  * ALSA: Add a reference counter to card instance
    - LP: #1081676
  * ALSA: Avoid endless sleep after disconnect
    - LP: #1081676
  * drm/radeon: fix typo in evergreen_mc_resume()
    - LP: #1081676
  * USB: mos7840: remove unused variable
    - LP: #1081676
  * rtnetlink: Fix problem with buffer allocation
    - LP: #1081676
  * rtnetlink: fix rtnl_calcit() and rtnl_dump_ifinfo()
    - LP: #1081676
  * gpio-timberdale: fix a potential wrapping issue
    - LP: #1081676
  * cfg80211: fix antenna gain handling
    - LP: #1081676
  * drm/i915: fix overlay on i830M
    - LP: #1081676
  * drm/i915: fixup infoframe support for sdvo
    - LP: #1081676
  * drm/i915: clear the entire sdvo infoframe buffer
    - LP: #1081676
  * crypto: cryptd - disable softirqs in cryptd_queue_worker to prevent
    data corruption
    - LP: #1081676
  * ARM: at91: at91sam9g10: fix SOC type detection
    - LP: #1081676
  * ARM: at91/i2c: change id to let i2c-gpio work
    - LP: #1081676
  * mac80211: Only process mesh config header on frames that RA_MATCH
    - LP: #1081676
  * mac80211: don't inspect Sequence Control field on control frames
    - LP: #1081676
  * mac80211: fix SSID copy on IBSS JOIN
    - LP: #1081676
  * wireless: drop invalid mesh address extension frames
    - LP: #1081676
  * mac80211: check managem...

[Adam Conrad (adconrad)]

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

[linrunner (linrunner)]

Just for the record: yes, the patch resolves the bug for my machines.