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 f24ba846133d0edec785ac6430d4daf6e9c93a09 ]
The "Downstream Port Containment related Enhancements" ECN of Jan 28, 2019 (document 12888 below), defined the EDR_PORT_DPC_ENABLE_DSM function with Revision ID 5 with Arg3 being an integer. But when the ECN was integrated into PCI Firmware r3.3, sec 4.6.12, it was defined as Revision ID 6 with Arg3 being a package containing an integer.
The implementation in acpi_enable_dpc() supplies a package as Arg3 (arg4 in the code), but it previously specified Revision ID 5. Align this with PCI Firmware r3.3 by using Revision ID 6.
If firmware implemented per the ECN, its Revision 5 function would receive a package as Arg3 when it expects an integer, so acpi_enable_dpc() would likely fail. If such firmware exists and lacks a Revision 6 function that expects a package, we may have to add support for Revision 5.
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 | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c index 5f4914d313a17..fa085677c91de 100644 --- a/drivers/pci/pcie/edr.c +++ b/drivers/pci/pcie/edr.c @@ -32,10 +32,10 @@ static int acpi_enable_dpc(struct pci_dev *pdev) int status = 0;
/* - * Behavior when calling unsupported _DSM functions is undefined, - * so check whether EDR_PORT_DPC_ENABLE_DSM is supported. + * Per PCI Firmware r3.3, sec 4.6.12, EDR_PORT_DPC_ENABLE_DSM is + * optional. Return success if it's not implemented. */ - if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 6, 1ULL << EDR_PORT_DPC_ENABLE_DSM)) return 0;
@@ -46,12 +46,7 @@ static int acpi_enable_dpc(struct pci_dev *pdev) argv4.package.count = 1; argv4.package.elements = &req;
- /* - * Per Downstream Port Containment Related Enhancements ECN to PCI - * Firmware Specification r3.2, sec 4.6.12, EDR_PORT_DPC_ENABLE_DSM is - * optional. Return success if it's not implemented. - */ - obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 6, EDR_PORT_DPC_ENABLE_DSM, &argv4); if (!obj) return 0;