[Skiboot] [PATCH 1/4] hw/phb4: Skip FRESET PERST when coming from CRESET

Stewart Smith stewart at linux.ibm.com
Fri Mar 29 16:02:48 AEDT 2019

"Oliver O'Halloran" <oohall at gmail.com> writes:
> PERST is asserted at the beginning of the CRESET process to prevent
> the downstream device from interacting with the host while the PHB logic
> is being reset and re-initialised. There is at least a 100ms wait during
> the CRESET processing so it's not necessary to wait this time again
> in the FRESET handler.
> This patch extends the delay after re-setting the PHB logic to extend
> to the 250ms PERST wait period that we typically use and sets the
> skip_perst flag so that we don't wait this time again in the FRESET
> handler.
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> NB: In boot we jump directly into the FRESET_START state and skip CRESET
> entirely so this patch should not affect boot time at all. It might make
> fast-reset slightly faster.

Series merged to master as of 722cf1c2ed56907fd9cc64c3f406f998d7e44992
and I hope (with fix discussed on internal Slack), that we're all okay
(I couldn't really recreate that EEH it turns out, but the fix *seemed*
to make sense... so I'm only *slightly* YOLOing it?)

Stewart Smith
OPAL Architect, IBM.

More information about the Skiboot mailing list