This is a note to let you know that I've just added the patch titled
PCI/EDR: Align EDR_PORT_DPC_ENABLE_DSM with PCI Firmware r3.3
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-edr-align-edr_port_dpc_enable_dsm-with-pci-firmw.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 36115f1b7f2b0d9dcc6ed018753ed0a576752e86
Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Date: Wed May 1 02:25:43 2024 +0000
PCI/EDR: Align EDR_PORT_DPC_ENABLE_DSM with PCI Firmware r3.3
[ 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.kuppuswamy@xxxxxxxxxxxxxxx
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@xxxxxxxxxxxxxxx>
[bhelgaas: split into two patches, update commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Tested-by: Satish Thatchanamurthy <Satish.Thatchanamurt@xxxxxxxx> # one platform
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index 87734e4c3c204..5b5a502363c00 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;
