Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/42455 )
Change subject: nb/intel/sandybridge/gma.c: Correct deasserting force wake on IVB ......................................................................
Patch Set 2:
I know it's a lot of work, but I think all the changes in this series (even individual bits) should be tested separately if they fix anything.
It's quite difficult to do given that we have no idea what these bits mean. Or by testing you mean running it for a couple of days and making sure the system is still stable?
Basically yes, do changes step by step until your problematic system is stable. If we merge this without detailed information which parts actually fix something, and then something goes wrong, it would be reverted as a whole.