drm/nouveau/acpi: fix check for power resources support

Check whether the kernel really supports power resources for a device,
otherwise the power might not be removed when the device is runtime
suspended (DSM should still work in these cases where PR does not).

This is a workaround for a problem where ACPICA and Windows 10 differ in
behavior. ACPICA does not correctly enumerate power resources within a
conditional block (due to delayed execution of such blocks) and as a
result power_resources is set to false even if _PR3 exists.

Fixes: 62ee86db5cb1 ("drm/nouveau/acpi: fix lockup with PCIe runtime PM")
Link: https://bugs.freedesktop.org/show_bug.cgi?id=98398
Reported-and-tested-by: Rick Kerkhof <rick.2889@gmail.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index dc57b628e07473ad6e0810085c5fd960ef6b49bc..193573d191e520a12ccdde4a791ebdf8e64a334c 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -240,7 +240,8 @@ static bool nouveau_pr3_present(struct pci_dev *pdev)
        if (!parent_adev)
                return false;
 
-       return acpi_has_method(parent_adev->handle, "_PR3");
+       return parent_adev->power.flags.power_resources &&
+               acpi_has_method(parent_adev->handle, "_PR3");
 }
 
 static void nouveau_dsm_pci_probe(struct pci_dev *pdev, acpi_handle *dhandle_out,