| Message ID | 20241214104117.17973-1-zhoushengqing@ttyinfo.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [PATCHv3] PCI/ACPI: _DSM PRESERVE_BOOT_CONFIG function rev id doesn't match with spec | expand |
Hi Bjorn, Please ignore this post. On Sat, 14 Dec 2024 10:41:17 +0000, Zhou shengqing wrote: > Per PCI Firmware Specification Revision 3.3 Table 4-7 _DSM Definitions > for PCI. Preserve PCI Boot Configuration Initial Revision ID changed to 2. > But the code remains unchanged, still 1. > > v3:try revision id 1 first, then try revision id 2. > v2:add Fixes tag. > > Fixes: 9d7d5db8e78e ("PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()") > > Signed-off-by: Zhou Shengqing <zhoushengqing@ttyinfo.com> > --- > drivers/pci/pci-acpi.c | 40 +++++++++++++++++++++++++++++++--------- > 1 file changed, 31 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index af370628e583..ae3b315d708c 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -126,16 +126,38 @@ bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge) > union acpi_object *obj; > > /* > - * Evaluate the "PCI Boot Configuration" _DSM Function. If it > - * exists and returns 0, we must preserve any PCI resource > - * assignments made by firmware for this host bridge. > + * Per PCI Firmware r3.2, released Jan 26, 2015, > + * DSM_PCI_PRESERVE_BOOT_CONFIG Revision ID is 1. > + * But PCI Firmware r3.3, released Jan 20, 2021, > + * changed sec 4.6.5 to say > + * "lowest valid Revision ID value: 2". So try revision 1 > + * first for old platform, then try revision 2. > */ > - obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev), > - &pci_acpi_dsm_guid, > - 1, DSM_PCI_PRESERVE_BOOT_CONFIG, > - NULL, ACPI_TYPE_INTEGER); > - if (obj && obj->integer.value == 0) > - return true; > + if (acpi_check_dsm(ACPI_HANDLE(&host_bridge->dev), &pci_acpi_dsm_guid, 1, > + 1ULL << DSM_PCI_PRESERVE_BOOT_CONFIG)) { > + /* > + * Evaluate the "PCI Boot Configuration" _DSM Function. If it > + * 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(&host_bridge->dev), > + &pci_acpi_dsm_guid, > + 1, DSM_PCI_PRESERVE_BOOT_CONFIG, > + NULL, ACPI_TYPE_INTEGER); > + if (obj && obj->integer.value == 0) > + return true; > + } > + > + if (acpi_check_dsm(ACPI_HANDLE(&host_bridge->dev), &pci_acpi_dsm_guid, 2, > + 1ULL << DSM_PCI_PRESERVE_BOOT_CONFIG)) { > + obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev), > + &pci_acpi_dsm_guid, > + 2, DSM_PCI_PRESERVE_BOOT_CONFIG, > + NULL, ACPI_TYPE_INTEGER); > + if (obj && obj->integer.value == 0) > + return true; > + } > + > ACPI_FREE(obj); > } > > -- > 2.39.2
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index af370628e583..ae3b315d708c 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -126,16 +126,38 @@ bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge) union acpi_object *obj; /* - * Evaluate the "PCI Boot Configuration" _DSM Function. If it - * exists and returns 0, we must preserve any PCI resource - * assignments made by firmware for this host bridge. + * Per PCI Firmware r3.2, released Jan 26, 2015, + * DSM_PCI_PRESERVE_BOOT_CONFIG Revision ID is 1. + * But PCI Firmware r3.3, released Jan 20, 2021, + * changed sec 4.6.5 to say + * "lowest valid Revision ID value: 2". So try revision 1 + * first for old platform, then try revision 2. */ - obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev), - &pci_acpi_dsm_guid, - 1, DSM_PCI_PRESERVE_BOOT_CONFIG, - NULL, ACPI_TYPE_INTEGER); - if (obj && obj->integer.value == 0) - return true; + if (acpi_check_dsm(ACPI_HANDLE(&host_bridge->dev), &pci_acpi_dsm_guid, 1, + 1ULL << DSM_PCI_PRESERVE_BOOT_CONFIG)) { + /* + * Evaluate the "PCI Boot Configuration" _DSM Function. If it + * 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(&host_bridge->dev), + &pci_acpi_dsm_guid, + 1, DSM_PCI_PRESERVE_BOOT_CONFIG, + NULL, ACPI_TYPE_INTEGER); + if (obj && obj->integer.value == 0) + return true; + } + + if (acpi_check_dsm(ACPI_HANDLE(&host_bridge->dev), &pci_acpi_dsm_guid, 2, + 1ULL << DSM_PCI_PRESERVE_BOOT_CONFIG)) { + obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev), + &pci_acpi_dsm_guid, + 2, DSM_PCI_PRESERVE_BOOT_CONFIG, + NULL, ACPI_TYPE_INTEGER); + if (obj && obj->integer.value == 0) + return true; + } + ACPI_FREE(obj); }
Per PCI Firmware Specification Revision 3.3 Table 4-7 _DSM Definitions for PCI. Preserve PCI Boot Configuration Initial Revision ID changed to 2. But the code remains unchanged, still 1. v3:try revision id 1 first, then try revision id 2. v2:add Fixes tag. Fixes: 9d7d5db8e78e ("PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()") Signed-off-by: Zhou Shengqing <zhoushengqing@ttyinfo.com> --- drivers/pci/pci-acpi.c | 40 +++++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 9 deletions(-)