[coreboot-gerrit] Change in coreboot[master]: mb/google/zork: update USB 2.0 controller Lane Parameter for dirinboz

[Martin Roth (Code Review)]

Attention is currently required from: Kevin Chiu, Furquan Shaikh, Bhanu Prakash Maiya, Paul Menzel, Eric Peers.
Martin Roth has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/47857 )

Change subject: mb/google/zork: update USB 2.0 controller Lane Parameter for dirinboz
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Patch Set 2:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/47857/comment/0092a507_33adec86 
PS2, Line 11: COMPDISTUNE(COMPDISTUNE0): 0x7
> Where did you get these from?

Looking at the bug, these were calculated through a very lengthy process starting with a failing eye diagram.  The EEs and AMD calculated the needed changes from the default values which were verified through testing.

https://review.coreboot.org/c/coreboot/+/47857/comment/f2220325_ad2cb772 
PS2, Line 15: TEST=emerge-zork coreboot
> How did you verify those?

The values were tested empirically with an eye diagram mf the USB signals.