Attention is currently required from: Felix Singer, Nico Huber, Angel Pons, Patrick Rudolph. Benjamin Doron has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50045 )
Change subject: soc/intel/skylake: Set "PEG?Enable" UPD directly ......................................................................
Patch Set 4:
(2 comments)
Patchset:
PS4:
I'm still not convinced this patch can really improve much. […]
Initially, the idea was to cleanup the function by avoiding unnecessary configuration. However, if coreboot prefers to guarantee certain settings, rather than using a default, then you're right, it's not necessary.
File src/soc/intel/skylake/romstage/romstage.c:
https://review.coreboot.org/c/coreboot/+/50045/comment/5a873b1c_fe97fc7f PS4, Line 174: if (dev && dev->enabled) {
Now this will leave FSP UPDs unprogrammed for disabled PEG RPs. If you want to avoid rewriting the UPD, you have to write the desired values in one statement, and actually remove the write in the if-block:
m_cfg->Peg0Enable = dev && dev->enabled ? 2 : 0; if (m_cfg->Peg0Enable) { ...
How many nanoseconds does this shave off the boot time, though?
The difference is definitely within margin of error, but that does look cleaner.