i915: kernel errors at resume

[Paul Bolle]

0) On a laptop I use I've ran into i915 kernel errors at resume. I see
these only every now and then: not on all resumes. The pattern of these
errors (and preceding messages) is basically always like this:

<6>[14673.762529] [drm] Changing LVDS panel from (+hsync, +vsync) to (-hsync, -vsync)
<6>[14673.824599] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state
<3>[14673.825071] render error detected, EIR: 0x00000010
<3>[14673.825071] page table error
<3>[14673.825071]   PGTBL_ER: 0x00000100
<3>[14673.825071] [drm:i915_report_and_clear_eir] *ERROR* EIR stuck: 0x00000010, masking

1) I've only noticed this because:
- I tend to check for KERN_ERR messages in the logs; and
- the errors (ie, the messages with a <3> prefix) look scary when text
mode briefly flashes by at suspend and at resume.
Otherwise the display on this machine seems to work just fine.

2) The logs on this machine only have information for v3.3 based
kernels. I haven't checked whether earlier kernels also do this. Nor
have I checked whether this is fixed in the current v3.4 release
candidates.

3) Some similar reports, but for messages printed at boot:
http://lists.freedesktop.org/archives/dri-devel/2011-January/007302.html
http://lists.freedesktop.org/archives/dri-devel/2012-January/018158.html

4) What can I do to (help) make these messages go away?


Paul Bolle