[Skiboot] [PATCH v2] phb4/capp: Calculate STQ/DMA read engines based on link-width for PEC

Stewart Smith stewart at linux.ibm.com
Wed Jul 11 15:08:54 AEST 2018

Vaibhav Jain <vaibhav at linux.ibm.com> writes:
> Presently in CAPI mode the number of STQ/DMA-read engines allocated on
> PEC2 for CAPP is fixed to 6 and 0-30 respectively irrespective of the
> PCI link width. These values are only suitable for x8 cards and
> quickly run out if a x16 card is plugged to a PEC2 attached slot. This
> usually manifests as CAPP reporting TLBI timeout due to these messages
> getting stalled due to insufficient STQs.
> To fix this we update enable_capi_mode() to check if PEC2 chiplet is
> in x16 mode and if yes then we allocate 4/0-47 STQ/DMA-read engines
> for the CAPP traffic.
> Cc: stable # v5.7+
> Fixes: 37ea3cfdc852("capi: Enable capi mode for PHB4")
> Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>

Thanks, merged to master as of 47c09cdfe7a34843387c968ce75cea8dc578ab91
and to 6.0.x as of 70e0dc77f597c0062f9ab4471cab69a655c39cd4

Stewart Smith
OPAL Architect, IBM.

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