PCI: Add a helper to check Power Resource Requirements _PR3 existence
A driver may want to know the existence of _PR3, to choose different
runtime suspend behavior. A user will be add in next patch.
This is mostly the same as nouveau_pr3_present().
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20191018073848.14590-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e7982af..1df99d9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5856,6 +5856,24 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
return 0;
}
+#ifdef CONFIG_ACPI
+bool pci_pr3_present(struct pci_dev *pdev)
+{
+ struct acpi_device *adev;
+
+ if (acpi_disabled)
+ return false;
+
+ adev = ACPI_COMPANION(&pdev->dev);
+ if (!adev)
+ return false;
+
+ return adev->power.flags.power_resources &&
+ acpi_has_method(adev->handle, "_PR3");
+}
+EXPORT_SYMBOL_GPL(pci_pr3_present);
+#endif
+
/**
* pci_add_dma_alias - Add a DMA devfn alias for a device
* @dev: the PCI device for which alias is added