Re: [PATCH] PCI/DPC: Yet another quirk for PIO log size on Intel Raptor Lake-P

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Jan 02, 2025 at 05:43:13PM +0100, Takashi Iwai wrote:
> There is yet another PCI entry for Intel Raptor Lake-P that shows the
>   error "DPC: RP PIO log size 0 is invalid":
>   0000:00:07.0 PCI bridge [0604]: Intel Corporation Raptor Lake-P Thunderbolt 4 PCI Express Root Port #0 [8086:a76e]
>   0000:00:07.2 PCI bridge [0604]: Intel Corporation Raptor Lake-P Thunderbolt 4 PCI Express Root Port #2 [8086:a72f]
> 
> Add the corresponding quirk entry for 8086:a72f.
> 
> Note that the one for 8086:a76e has been already added by the commit
> 627c6db20703 ("PCI/DPC: Quirk PIO log size for Intel Raptor Lake Root
> Ports").

Intel folks, what's the long-term resolution of this?  I'm kind of
tired of adding quirks like this.  So far we have these (not including
the current patch), dating back to Aug 2022:

  627c6db20703 ("PCI/DPC: Quirk PIO log size for Intel Raptor Lake Root Ports")
  3b8803494a06 ("PCI/DPC: Quirk PIO log size for Intel Ice Lake Root Ports")
  5459c0b70467 ("PCI/DPC: Quirk PIO log size for certain Intel Root Ports")

I *thought* this problem was caused by BIOS defects that were supposed
to be fixed, but nothing seems to be happening.

If Linux can't figure out the correct value by itself (and I assume it
can't because we wouldn't need the register if we could), maybe we
can just silently ignore it and live without the RP logs?

> Link: https://bugzilla.suse.com/show_bug.cgi?id=1234623
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  drivers/pci/quirks.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 76f4df75b08a..4ed3704ce92e 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -6253,6 +6253,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2b, dpc_log_size);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2d, dpc_log_size);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2f, dpc_log_size);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a31, dpc_log_size);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa72f, dpc_log_size);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa73f, dpc_log_size);
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa76e, dpc_log_size);
>  #endif
> -- 
> 2.43.0
>