kernel-packages team mailing list archive

[spezimass <spezimass@xxxxxxxxx>]

using "acpi_backlight=vendor" on Saucy.

Before suspend & resume the behaviour of the led-backlight pressing F1 or F2 key is adjustable.
Checking the register `/sys/class/backlight/intel_backlight/brightness` the range from 0 to 2770 can be operated in 21 steps.
After resume still the full range is triggered with the F1 to F2 keys, but here the backlight is turned off completely for all values less than 2280 and fully turned on for all values greater 2290.

Setting the brightness with `echo 2289 >
/sys/class/backlight/intel_backlight/brightness` the led backlight
starts to flicker in a period of approx 1sec.

DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-12-generic 3.11.0-12.19 [modified: boot/vmlinuz-3.11.0-12-generic]
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.12.5-0ubuntu2
Architecture: amd64
InstallationDate: Installed on 2013-10-17 (1 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: Apple Inc. MacBookAir6,2
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-12-generic.efi.signed root=UUID=77b6a0d2-1d2f-480c-9e22-730bc9b73fed ro pcie_aspm=force i915.i915_enable_rc6=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1 acpi_backlight=vendor
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-12-generic N/A
 linux-backports-modules-3.11.0-12-generic N/A
 linux-firmware 1.116

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1197482

Title:
  After suspend/resume, screen is dark for brighness levels below 13
  with i915 driver on MacBook Air 6,2

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  After installing Raring on my 2013 MacBook Air 6,2, I find that
  sometimes when resuming from suspend, the screen is dark. I have
  tracked this down to the i915 driver, where the screen brightness can
  be adjusted between levels 0-15. This works correctly after boot, with
  0 being dark and 15 the brightest.

  Sometimes after suspend/resume, the screen is equally dark between
  levels 0-12, and seems to be equally bright for levels 13-15
  (brightest). I say sometimes, because it's not every time. It _might_
  be after the second or third suspend/resume, but I'm not yet sure how
  to repeat it.

  When this happens, I have to kill lightum, the backlight/keyboard
  monitoring daemon, and manually set the brightness using the sys
  filesystem:

  echo '15' | sudo tee
  /sys/devices/pci0000\:00/0000\:00\:02.0/backlight/acpi_video0/brightness

  ProblemType: Bug
  DistroRelease: Ubuntu 13.04
  Package: linux-image-3.8.0-25-generic 3.8.0-25.37
  ProcVersionSignature: Ubuntu 3.8.0-25.37-generic 3.8.13
  Uname: Linux 3.8.0-25-generic x86_64
  NonfreeKernelModules: wl
  ApportVersion: 2.9.2-0ubuntu8.1
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  linus      1939 F.... pulseaudio
  CRDA:
   country SE:
   	(2402 - 2482 @ 40), (N/A, 20)
   	(5170 - 5250 @ 40), (N/A, 20)
   	(5250 - 5330 @ 40), (N/A, 20), DFS
   	(5490 - 5710 @ 40), (N/A, 27), DFS
  Date: Wed Jul  3 19:23:53 2013
  HibernationDevice:
   RESUME=/dev/mapper/cryptswap1
   #RESUME=UUID=7625120b-1951-4a58-8da6-1c47db358631
  MachineType: Apple Inc. MacBookAir6,2
  MarkForUpload: True
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-25-generic root=UUID=2f08800d-d161-46e7-87b6-0f88e86890af ro i915.i915_enable_rc6=3 libata.force=1:noncq resume=/dev/sda4 quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.8.0-25-generic N/A
   linux-backports-modules-3.8.0-25-generic  N/A
   linux-firmware                            1.106
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 05/24/2013
  dmi.bios.vendor: Apple Inc.
  dmi.bios.version: MBA61.88Z.0099.B00.1305241529
  dmi.board.asset.tag: Base Board Asset Tag#
  dmi.board.name: Mac-7DF21CB3ED6977E5
  dmi.board.vendor: Apple Inc.
  dmi.board.version: MacBookAir6,2
  dmi.chassis.type: 10
  dmi.chassis.vendor: Apple Inc.
  dmi.chassis.version: Mac-7DF21CB3ED6977E5
  dmi.modalias: dmi:bvnAppleInc.:bvrMBA61.88Z.0099.B00.1305241529:bd05/24/2013:svnAppleInc.:pnMacBookAir6,2:pvr1.0:rvnAppleInc.:rnMac-7DF21CB3ED6977E5:rvrMacBookAir6,2:cvnAppleInc.:ct10:cvrMac-7DF21CB3ED6977E5:
  dmi.product.name: MacBookAir6,2
  dmi.product.version: 1.0
  dmi.sys.vendor: Apple Inc.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1197482/+subscriptions