kernel-packages team mailing list archive

[Alberto Aguirre <albaguirre@xxxxxxxxx>]

I debugged a bit further on the waking from sleep issue - it actually
also happens when changing modes through xrandr so not really related to
waking from S3, just turning off/on the display.

The display in the UX302LG/LA needs to be run at 24-bit apparently - the
current intel-gfx code (including in drm-intel-nightly) is clamping to
18bpp due to the BIOS advertising such info in the VBT (the same
behavior is seen with CSM and nonCSM mode).

If you remove the clamping, then everything works (display up at boot, modesetting works, waking from sleep works)
 - you don't really need commit c26fe8e5eb34c18aa9ab60fcf4c3150663a52306 BTW, just removing the clamping to run the pipe at 24bpp fixes all the blank screen issues.

This behavior was noted on other laptops as described in the intel-gfx bug:
https://bugzilla.kernel.org/show_bug.cgi?id=59841

As you can see in the bug description above, the temporary solution that's been merged in 3.12 was this hack:
https://bugzilla.kernel.org/attachment.cgi?id=111321&action=diff

Not entirely sure why that is not working for the UX302LG/LA yet (in
fact I don't see dp_get_config called at all for some reason, so the
hack does not go into effect).


** Bug watch added: Linux Kernel Bug Tracker #59841
   http://bugzilla.kernel.org/show_bug.cgi?id=59841

** Patch added: "0001-i915-Ignore-eDP-clamping-to-BIOS-provided-VBT-value.patch"
   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1265544/+attachment/3946655/+files/0001-i915-Ignore-eDP-clamping-to-BIOS-provided-VBT-value.patch

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https://bugs.launchpad.net/bugs/1265544

Title:
  8086:0a16 [UX302LG] black screen on boot 3.12.0-7

Status in “linux” package in Ubuntu:
  In Progress

Bug description:
  Same description/workaround as
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1263015

  I tried both Enable CSM and non-CSM boot.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.12.0-7-generic 3.12.0-7.15
  ProcVersionSignature: Ubuntu 3.12.0-7.15-generic 3.12.4
  Uname: Linux 3.12.0-7-generic x86_64
  ApportVersion: 2.12.7-0ubuntu3
  Architecture: amd64
  Date: Thu Jan  2 09:59:33 2014
  HibernationDevice: RESUME=UUID=e6458b44-fdb9-4db5-8cac-40ee0bbf9cf6
  InstallationDate: Installed on 2013-12-31 (1 days ago)
  InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20131231)
  Lsusb:
   Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
   Bus 001 Device 004: ID 03eb:8a03 Atmel Corp.
   Bus 001 Device 003: ID 1bcf:2987 Sunplus Innovation Technology Inc.
   Bus 001 Device 002: ID 8087:07dc Intel Corp.
   Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  MachineType: ASUSTeK COMPUTER INC. UX302LG
  ProcFB: 0 simple
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.12.0-7-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro recovery nomodeset
  RelatedPackageVersions:
   linux-restricted-modules-3.12.0-7-generic N/A
   linux-backports-modules-3.12.0-7-generic  N/A
   linux-firmware                            1.117
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 10/30/2013
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: UX302LG.207
  dmi.board.asset.tag: ATN12345678901234567
  dmi.board.name: UX302LG
  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.:bvrUX302LG.207:bd10/30/2013:svnASUSTeKCOMPUTERINC.:pnUX302LG:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX302LG:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
  dmi.product.name: UX302LG
  dmi.product.version: 1.0
  dmi.sys.vendor: ASUSTeK COMPUTER INC.

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