From: Nirmoy Das Date: Wed, 17 Dec 2025 15:45:29 +0000 (-0800) Subject: PCI: Add PCI_BRIDGE_NO_ALIAS quirk for ASPEED AST1150 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=550a190494a0d3e933dd6f3b2e9c430f94a30a8c;p=thirdparty%2Fkernel%2Flinux.git PCI: Add PCI_BRIDGE_NO_ALIAS quirk for ASPEED AST1150 ASPEED BMC controllers have VGA and USB functions behind a PCIe-to-PCI bridge that causes them to share the same StreamID: [e0]---00.0-[e1-e2]----00.0-[e2]--+-00.0 ASPEED Graphics Family \-02.0 ASPEED USB Controller Both devices get StreamID 0x5e200 due to bridge aliasing, causing the USB controller to be rejected with 'Aliasing StreamID unsupported'. Per ASPEED, the AST1150 doesn't use a real PCI bus and always forwards the original Requester ID from downstream devices rather than replacing it with any alias. Add a new PCI_DEV_FLAGS_PCI_BRIDGE_NO_ALIAS flag and apply it to the AST1150. Suggested-by: Jason Gunthorpe Signed-off-by: Nirmoy Das Signed-off-by: Bjorn Helgaas Reviewed-by: Robin Murphy Reviewed-by: Jason Gunthorpe Link: https://patch.msgid.link/20251217154529.377586-2-nirmoyd@nvidia.com --- diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index b9c252aa6fe08..7404fb0ff146f 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4453,6 +4453,16 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_BROADCOM, 0x9000, DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_BROADCOM, 0x9084, quirk_bridge_cavm_thrx2_pcie_root); +/* + * AST1150 doesn't use a real PCI bus and always forwards the requester ID + * from downstream devices. + */ +static void quirk_aspeed_pci_bridge_no_alias(struct pci_dev *pdev) +{ + pdev->dev_flags |= PCI_DEV_FLAGS_PCI_BRIDGE_NO_ALIAS; +} +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ASPEED, 0x1150, quirk_aspeed_pci_bridge_no_alias); + /* * Intersil/Techwell TW686[4589]-based video capture cards have an empty (zero) * class code. Fix it. diff --git a/drivers/pci/search.c b/drivers/pci/search.c index e6e84dc62e826..e3d3177fce549 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -86,6 +86,8 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, case PCI_EXP_TYPE_DOWNSTREAM: continue; case PCI_EXP_TYPE_PCI_BRIDGE: + if (tmp->dev_flags & PCI_DEV_FLAGS_PCI_BRIDGE_NO_ALIAS) + continue; ret = fn(tmp, PCI_DEVID(tmp->subordinate->number, PCI_DEVFN(0, 0)), data); diff --git a/include/linux/pci.h b/include/linux/pci.h index 864775651c6fa..48d5b9dac5f1e 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -248,6 +248,11 @@ enum pci_dev_flags { PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12), /* Device requires write to PCI_MSIX_ENTRY_DATA before any MSIX reads */ PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST = (__force pci_dev_flags_t) (1 << 13), + /* + * PCIe to PCI bridge does not create RID aliases because the bridge is + * integrated with the downstream devices and doesn't use real PCI. + */ + PCI_DEV_FLAGS_PCI_BRIDGE_NO_ALIAS = (__force pci_dev_flags_t) (1 << 14), }; enum pci_irq_reroute_variant {