Re: [PATCH 1/3] PCI: Call PCI ACPI _DSM with consistent revision argument

Mario Limonciello <mario.limonciello@xxxxxxx> · Thu, 30 Nov 2023 13:30:36 -0600

On 11/30/2023 07:34, Rafael J. Wysocki wrote:
On Fri, Nov 10, 2023 at 9:32 PM Mario Limonciello
<mario.limonciello@xxxxxxx> wrote:

The PCI ACPI _DSM is called across multiple places in the PCI core
with different arguments for the revision.

The PCI firmware specification specifies that this is an incorrect
behavior.
"OSPM must invoke all Functions other than Function 0 with the
  same Revision ID value"

Link: https://members.pcisig.com/wg/PCI-SIG/document/15350
       PCI Firmware specification 3.3, section 4.6
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>


Thanks!

and I haven't seen much activity related to this series, so I'm not
sure what's happening to it.

Regardless, I think that the remaining two patches are better sent
along with the first users of the new APIs.

Bjorn,

If you agree, can you please queue up the first patch?  I'll shuffle the 
others into the back of my mind for if/when they're needed.

Thanks!

---
  drivers/acpi/pci_root.c  |  3 ++-
  drivers/pci/pci-acpi.c   |  6 ++++--
  drivers/pci/pci-label.c  |  4 ++--
  drivers/pci/pcie/edr.c   | 13 +++++++------
  include/linux/pci-acpi.h |  1 +
  5 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 58b89b8d950e..bca2270a93d4 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -1055,7 +1055,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
          * exists and returns 0, we must preserve any PCI resource
          * assignments made by firmware for this host bridge.
          */
-       obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1,
+       obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge),
+                                     &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                                       DSM_PCI_PRESERVE_BOOT_CONFIG, NULL, ACPI_TYPE_INTEGER);
         if (obj && obj->integer.value == 0)
                 host_bridge->preserve_config = 1;
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 004575091596..bea72e807817 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -28,6 +28,7 @@
  const guid_t pci_acpi_dsm_guid =
         GUID_INIT(0xe5c937d0, 0x3553, 0x4d7a,
                   0x91, 0x17, 0xea, 0x4d, 0x19, 0xc3, 0x43, 0x4d);
+const int pci_acpi_dsm_rev = 5;

  #if defined(CONFIG_PCI_QUIRKS) && defined(CONFIG_ARM64)
  static int acpi_get_rc_addr(struct acpi_device *adev, struct resource *res)
@@ -1215,7 +1216,8 @@ void acpi_pci_add_bus(struct pci_bus *bus)
         if (!pci_is_root_bus(bus))
                 return;

-       obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 3,
+       obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge),
+                                     &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                                       DSM_PCI_POWER_ON_RESET_DELAY, NULL, ACPI_TYPE_INTEGER);
         if (!obj)
                 return;
@@ -1376,7 +1378,7 @@ static void pci_acpi_optimize_delay(struct pci_dev *pdev,
         if (bridge->ignore_reset_delay)
                 pdev->d3cold_delay = 0;

-       obj = acpi_evaluate_dsm_typed(handle, &pci_acpi_dsm_guid, 3,
+       obj = acpi_evaluate_dsm_typed(handle, &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                                       DSM_PCI_DEVICE_READINESS_DURATIONS, NULL,
                                       ACPI_TYPE_PACKAGE);
         if (!obj)
diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index 0c6446519640..91bdd04029f0 100644
--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -41,7 +41,7 @@ static bool device_has_acpi_name(struct device *dev)
         if (!handle)
                 return false;

-       return acpi_check_dsm(handle, &pci_acpi_dsm_guid, 0x2,
+       return acpi_check_dsm(handle, &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                               1 << DSM_PCI_DEVICE_NAME);
  #else
         return false;
@@ -162,7 +162,7 @@ static int dsm_get_label(struct device *dev, char *buf,
         if (!handle)
                 return -1;

-       obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2,
+       obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                                 DSM_PCI_DEVICE_NAME, NULL);
         if (!obj)
                 return -1;
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index 5f4914d313a1..ab6a50201124 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -35,7 +35,7 @@ static int acpi_enable_dpc(struct pci_dev *pdev)
          * Behavior when calling unsupported _DSM functions is undefined,
          * so check whether EDR_PORT_DPC_ENABLE_DSM is supported.
          */
-       if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
+       if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                             1ULL << EDR_PORT_DPC_ENABLE_DSM))
                 return 0;

@@ -51,8 +51,9 @@ static int acpi_enable_dpc(struct pci_dev *pdev)
          * 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,
-                               EDR_PORT_DPC_ENABLE_DSM, &argv4);
+       obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid,
+                               pci_acpi_dsm_rev, EDR_PORT_DPC_ENABLE_DSM,
+                               &argv4);
         if (!obj)
                 return 0;

@@ -88,12 +89,12 @@ static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev)
          * Behavior when calling unsupported _DSM functions is undefined,
          * so check whether EDR_PORT_DPC_ENABLE_DSM is supported.
          */
-       if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
+       if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, pci_acpi_dsm_rev,
                             1ULL << EDR_PORT_LOCATE_DSM))
                 return pci_dev_get(pdev);

-       obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
-                               EDR_PORT_LOCATE_DSM, NULL);
+       obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid,
+                               pci_acpi_dsm_rev, EDR_PORT_LOCATE_DSM, NULL);
         if (!obj)
                 return pci_dev_get(pdev);

diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 078225b514d4..7966ef8f14b3 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -115,6 +115,7 @@ static inline void acpiphp_check_host_bridge(struct acpi_device *adev) { }
  #endif

  extern const guid_t pci_acpi_dsm_guid;
+extern const int pci_acpi_dsm_rev;

  /* _DSM Definitions for PCI */
  #define DSM_PCI_PRESERVE_BOOT_CONFIG           0x05
--
2.34.1










