[PATCH 4.3 194/200] drm/nouveau/pmu: do not assume a PMU is present

[Greg Kroah-Hartman]

4.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexandre Courbot <acourbot@xxxxxxxxxx>

commit 579b7c58215329803ce184704463de09f0f310ac upstream.

Some devices may not have a PMU. Avoid a NULL pointer dereference in
such cases by checking whether the pointer given to nvkm_pmu_pgob() is
valid.

Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
@@ -28,7 +28,7 @@
 void
 nvkm_pmu_pgob(struct nvkm_pmu *pmu, bool enable)
 {
-	if (pmu->func->pgob)
+	if (pmu && pmu->func->pgob)
 		pmu->func->pgob(pmu, enable);
 }