drm/nouveau/acpi: fix check for power resources support
commit7290da41b8da4a8a6819966cb9922170f5ae70c6
authorPeter Wu <peter@lekensteyn.nl>
Mon, 31 Oct 2016 22:48:22 +0000 (31 23:48 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 10 Nov 2016 15:38:54 +0000 (10 16:38 +0100)
tree108844773120f3431694009f1b34c45ca18cb63b
parentfd5f9e1e28cb170100653d915805407a47fc7809
drm/nouveau/acpi: fix check for power resources support

commit b0a6af8b34c9ad20894aa46f85f4bf59d444f286 upstream.

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: 692a17dcc292 ("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>
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/nouveau/nouveau_acpi.c