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
?
Best Answer
Dissecting the acronym, I get that MCH stands for 'Memory Controller Hub' with is an older name for the northbridge. This chip is part of your I/O controller hub.
As for SSKPD, there is not much information I can find other than what is in various intel manuals. Here is a snippet from one of them:
Unfortunately this doesn't give much information on what it is. According to Wikipedia, scratchpad is "special high-speed memory circuit used to hold small items of data for rapid retrieval."
Another piece of information is the log from the commit that added the warning:
So seemingly the value of the register has some meaning on some processors. There isn't anything I can find on the internet at this time which explains exactly what could go wrong by it having the wrong value, but I think this gives a good overall idea.
If you really want to dig further, you could email one of the guys who wrote or reviewed the commit.