Re: [PATCH v1] PCI/TPH: fold reserved completer encoding in get_rp_completer_type()

[sashiko-bot@kernel.org]

> get_rp_completer_type() returns the Root Port's "TPH Completer
> Supported" field (bits 13:12 of Device Capabilities 2) verbatim. The
> 0b10 encoding is reserved, but pcie_enable_tph() feeds the raw value
> into the requester type:
> 
> 	pdev->tph_req_type = min(pdev->tph_req_type, rp_req_type);
> 
> and later writes tph_req_type to the TPH Requester Enable field, which
> only defines 0b00 (disable), 0b01 (TPH only) and 0b11 (extended TPH).
> If a Root Port ever presents the reserved 0b10, that value could be
> written back to hardware, risking undefined behavior.
> 
> Fold the reserved encoding into "not supported" so only the three
> defined values can propagate.
> 
> Fixes: f69767a1ada3 ("PCI: Add TLP Processing Hints (TPH) support")
> Signed-off-by: Zhiping Zhang <zhipingz@meta.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260713214026.793795-1-zhipingz@meta.com?part=1