kernel-packages team mailing list archive

["Christopher M. Penalver" <christopher.m.penalver@xxxxxxxxx>]

Axel Mueller, the requested patch is available in Trusty as per http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-trusty.git;a=commit;h=051963d4832ed61e5ae74f5330b0a94489e101b9 . Please reopen if this doesn't work for you, and execute the following in a terminal:
apport-collect 722806

** Changed in: linux (Ubuntu)
       Status: Fix Committed => Invalid

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https://bugs.launchpad.net/bugs/722806

Title:
  Asus M2A-VM: kernel demanding EDID for an unconnected monitor

Status in The Linux Kernel:
  Fix Released
Status in “linux” package in Ubuntu:
  Invalid
Status in “linux” package in Fedora:
  Unknown

Bug description:
  There is a problem with mainboard Asus M2A-VM. There is no HDMI monitor connected (monitor uses DVI) but the kernel still tries to read the EDID. Thus, dmesg is spammed every 10 seconds with this message:
  [   21.383270] [drm:drm_edid_block_valid] *ERROR* Raw EDID:
  [   21.383305] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383307] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383310] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383312] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383314] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383317] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383319] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383322] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  [   21.383324] 
  [   21.383328] radeon 0000:01:05.0: HDMI-A-1: EDID block 0 invalid.
  [   21.383332] [drm:radeon_dvi_detect] *ERROR* HDMI-A-1: probed a monitor but no|invalid EDID

  X behaves very jerky because of the load caused by the kernel demanding the EDID every 10 seconds.
  For more info see https://bugzilla.redhat.com/show_bug.cgi?id=668196 and http://ubuntuforums.org/showthread.php?t=1607778

  I found three possible solutions to solve my problem:
  1) disable KMS by using the kernel parameter "radeon.modeset=0"
  Unfortunately, the X server will then segfault after a short time
  2) get the kernel source and patch the radeon driver, see http://ubuntuforums.org/showthread.php?t=1607778
  (the patch is not from me!)
  this works, but you have to patch the kernel after every update again
  3) execute the command
  "echo -n N > /sys/module/drm_kms_helper/parameters/poll"
  This will effectively stop the pollution of the dmesg (and all the quirky X behavior). This option does not exist in kernel 2.6.35 that's why I had update to kernel 2.6.38

  It would be fine if the kernel tries to read the EDID only once and
  then stops trying if it fails (see patch from solution #2).

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