[coreboot-gerrit] Change in coreboot[master]: mb/prodrive/hermes: Fix PCIe ClkSrc configuration

[Angel Pons (Code Review)]

Attention is currently required from: Patrick Rudolph, Christian Walter, Michael Niewöhner.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/58065 )

Change subject: mb/prodrive/hermes: Fix PCIe ClkSrc configuration
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Patch Set 2:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/58065/comment/43debb67_931b250d 
PS2, Line 10: Apparently, FSP does not turn off unused PCIe clock sources when using
> Same here; also, this doesn't make *any* sense to me tbh o.O […]

OK, this seems to be inaccurate. I think what happens is that the ICC (Integrated Clock Controller) part of the ME works differently when using CSME vs SPS firmware. I'll revise this.

https://review.coreboot.org/c/coreboot/+/58065/comment/dc3c45b8_2ce63b56 
PS2, Line 12: firmware.
> It's more likely that the 1:1 mapping of "SRC$ CLKREQ#" to pin in the new IFD causes problems. […]

All the CLKSRCs are configured as free-running (always on), so I'm not sure what CLKREQ# has to do with the issue. Swapping IFDs made no difference.