[ltp] drm/i915: "Wrong MCH_SSKPD value: 0x16040307"

Paul Bolle linux-thinkpad@linux-thinkpad.org
Wed, 30 Jul 2014 20:49:07 +0200

0) A ThinkPad X220 I use prints these messages at every boot and at
every resume:
    [drm] Wrong MCH_SSKPD value: 0x16040307
    [drm] This can cause pipe underruns and display issues.
    [drm] Please upgrade your BIOS to fix this.

These messages can be seen for every kernel that's still in the logs
(the oldest is v3.11 based).

1) I'm not sure whether I actually run into "pipe underruns" or "display
issues". Is there something specific I should look for?

2) Now it happens that this laptop already runs the latest BIOS. So, if
I were to contact Lenovo to see if they could release a BIOS update to
fix this, what should I ask them to do?

Paul Bolle