What is MCH_SSKPD warning in dmesg?

While i was reading dmesg log just to check that everything is fine, i met

[   18.956187] [drm] Wrong MCH_SSKPD value: 0x16040307
[   18.956190] [drm] This can cause pipe underruns and display issues.
[   18.956192] [drm] Please upgrade your BIOS to fix this.

Looks that it does not cause problems on my laptop, but what does this message stands for? What can it cause? Where can I read more about MCH_SSKPD?