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| author | Benjamin Herrenschmidt | 2019-06-15 02:23:57 +0200 |
|---|---|---|
| committer | Bjorn Helgaas | 2019-06-22 01:11:53 +0200 |
| commit | a78cf9657ba5426f54aa93a067c10d097944c082 (patch) | |
| tree | aa6cbc8b7f5808ff37b46a51ab37de03964fea79 /drivers/acpi | |
| parent | Linux 5.2-rc1 (diff) | |
| download | kernel-qcow2-linux-a78cf9657ba5426f54aa93a067c10d097944c082.tar.gz kernel-qcow2-linux-a78cf9657ba5426f54aa93a067c10d097944c082.tar.xz kernel-qcow2-linux-a78cf9657ba5426f54aa93a067c10d097944c082.zip | |
PCI/ACPI: Evaluate PCI Boot Configuration _DSM
Evaluate _DSM Function #5, the "PCI Boot Configuration" function. If the
result is 0, the OS should preserve any resource assignments made by the
firmware.
Link: https://lore.kernel.org/r/20190615002359.29577-2-benh@kernel.crashing.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/pci_root.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index c36781a9b493..0d57f817ef1e 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -894,6 +894,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, int node = acpi_get_node(device->handle); struct pci_bus *bus; struct pci_host_bridge *host_bridge; + union acpi_object *obj; info->root = root; info->bridge = device; @@ -930,6 +931,17 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL)) host_bridge->native_ltr = 0; + /* + * 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(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1, + IGNORE_PCI_BOOT_CONFIG_DSM, NULL); + if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0) + host_bridge->preserve_config = 1; + ACPI_FREE(obj); + pci_scan_child_bus(bus); pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info, info); |