PCI: Add ACS quirk for Pericom PI7C9X2G608 switches [12d8:2608]

[PATCH] PCI: Add ACS quirk for Pericom PI7C9X2G608 switches [12d8:2608]

Posted by Tim Harvey 4 days, 3 hours ago

The Pericom PI7C9X2G608 6-port Gen2 PCIe switch is also affected by
the PI7C9X2G errata per the errata document:
E2: ACS P2P Request Redirect Is Not Functional

Apply the same quirk to this PCI ID as well to apply the workaround
required if using ACS.

Fixes: acd61ffb2f16 ("PCI: Add ACS quirk for Pericom PI7C9X2G switches")
Cc: stable@vger.kernel.org
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
 drivers/pci/quirks.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index b09f27f7846f..27f7d56c9ac3 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6263,6 +6263,10 @@ DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0xb404,
 			 pci_fixup_pericom_acs_store_forward);
 DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0xb404,
 			 pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2608,
+			 pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2608,
+			 pci_fixup_pericom_acs_store_forward);
 
 static void nvidia_ion_ahci_fixup(struct pci_dev *pdev)
 {
-- 
2.34.1

Re: [PATCH] PCI: Add ACS quirk for Pericom PI7C9X2G608 switches [12d8:2608]

Posted by Bjorn Helgaas 3 days, 8 hours ago

[+to Nathan]

On Mon, Jul 20, 2026 at 02:57:18PM -0700, Tim Harvey wrote:
> The Pericom PI7C9X2G608 6-port Gen2 PCIe switch is also affected by
> the PI7C9X2G errata per the errata document:
> E2: ACS P2P Request Redirect Is Not Functional
> 
> Apply the same quirk to this PCI ID as well to apply the workaround
> required if using ACS.
> 
> Fixes: acd61ffb2f16 ("PCI: Add ACS quirk for Pericom PI7C9X2G switches")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tim Harvey <tharvey@gateworks.com>

Applied to pci/virtualization for v7.3, thanks!

Note that Sashiko found what looks like a legit pre-existing issue
with acd61ffb2f16 ("PCI: Add ACS quirk for Pericom PI7C9X2G
switches"):

  https://lore.kernel.org/all/20260720223203.A30841F000E9@smtp.kernel.org

> ---
>  drivers/pci/quirks.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b09f27f7846f..27f7d56c9ac3 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -6263,6 +6263,10 @@ DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0xb404,
>  			 pci_fixup_pericom_acs_store_forward);
>  DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0xb404,
>  			 pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2608,
> +			 pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2608,
> +			 pci_fixup_pericom_acs_store_forward);
>  
>  static void nvidia_ion_ahci_fixup(struct pci_dev *pdev)
>  {
> -- 
> 2.34.1
>