6.6-stable review patch. If anyone has any objections, please let me know.
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From: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com
[ Upstream commit e2e78a294a8a863898b781dbcf90e087eda3155d ]
The "Downstream Port Containment related Enhancements" ECN of Jan 28, 2019 (document 12888 below), defined the EDR_PORT_LOCATE_DSM function with Revision ID 5 with a return value encoding (Bits 2:0 = Function, Bits 7:3 = Device, Bits 15:8 = Bus). When the ECN was integrated into PCI Firmware r3.3, sec 4.6.13, Bit 31 was added to indicate success or failure.
Check Bit 31 for failure in acpi_dpc_port_get().
Link: https://lore.kernel.org/r/20240501022543.1626025-1-sathyanarayanan.kuppuswam... Link: https://members.pcisig.com/wg/PCI-SIG/document/12888 Fixes: ac1c8e35a326 ("PCI/DPC: Add Error Disconnect Recover (EDR) support") Signed-off-by: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com [bhelgaas: split into two patches, update commit log] Signed-off-by: Bjorn Helgaas bhelgaas@google.com Tested-by: Satish Thatchanamurthy Satish.Thatchanamurt@Dell.com # one platform Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pcie/edr.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c index fa085677c91de..e86298dbbcff6 100644 --- a/drivers/pci/pcie/edr.c +++ b/drivers/pci/pcie/edr.c @@ -80,8 +80,9 @@ static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev) u16 port;
/* - * Behavior when calling unsupported _DSM functions is undefined, - * so check whether EDR_PORT_DPC_ENABLE_DSM is supported. + * If EDR_PORT_LOCATE_DSM is not implemented under the target of + * EDR, the target is the port that experienced the containment + * event (PCI Firmware r3.3, sec 4.6.13). */ if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5, 1ULL << EDR_PORT_LOCATE_DSM)) @@ -98,6 +99,16 @@ static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev) return NULL; }
+ /* + * Bit 31 represents the success/failure of the operation. If bit + * 31 is set, the operation failed. + */ + if (obj->integer.value & BIT(31)) { + ACPI_FREE(obj); + pci_err(pdev, "Locate Port _DSM failed\n"); + return NULL; + } + /* * Firmware returns DPC port BDF details in following format: * 15:8 = bus