[S] Change in coreboot[master]: device/pciexp_device.c: Do not enable common clock if already active

[Paul Menzel (Code Review)]

Attention is currently required from: Subrata Banik, Werner Zeh.

Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/73310 )

Change subject: device/pciexp_device.c: Do not enable common clock if already active
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Patch Set 1:

(6 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/73310/comment/20747fc8_5b1e16ab 
PS1, Line 11: re-train
I would have thought it’s re-training.

https://review.coreboot.org/c/coreboot/+/73310/comment/0ff43e8c_745ceb55 
PS1, Line 14: FSP code
Which version?

https://review.coreboot.org/c/coreboot/+/73310/comment/760f0ef4_f581f489 
PS1, Line 18: re-train
Ditto.

https://review.coreboot.org/c/coreboot/+/73310/comment/0c562b60_6d7dfca6 
PS1, Line 26: In particular, link issues were discovered
            : with a Pericom PCIe switch (PI7C9X2G608) on mc_ehl1 where the link has
            : stalled for a while after the second re-train.
Out of curiosity, are two re-trainings spec-compliant, so this is actually a bug of the Pericom PCIe switch?

https://review.coreboot.org/c/coreboot/+/73310/comment/38ad74b5_65a36a93 
PS1, Line 33: and thus execution time
How much?

File src/device/pciexp_device.c:

https://review.coreboot.org/c/coreboot/+/73310/comment/251757b0_bd9d3ffe 
PS1, Line 205: 		printk(BIOS_INFO, "Common Clock Configuration already enabled\n");
Maybe:

PCIe: Common Clock Configuration already enabled, so skip it