drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL

commit 233709d2cd6bbaaeda0aeb8d11f6ca7f98563b39 upstream.

This can be the case when the GPU is powered off, e.g. via vgaswitcheroo
or runpm. When the GPU is powered up again, radeon_gart_table_vram_pin
flushes the TLB after setting rdev->gart.ptr to non-NULL.

Fixes panic on powering off R7xx GPUs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61529
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c
index 2e723651069bd7d084d393e25c741f122b4c5c79..4259a1fa323f5019f83c43ecddd4e7fbcc4bc563 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_gart.c
+++ b/drivers/gpu/drm/radeon/radeon_gart.c
@@ -249,8 +249,10 @@ void radeon_gart_unbind(struct radeon_device *rdev, unsigned offset,
                        }
                }
        }
-       mb();
-       radeon_gart_tlb_flush(rdev);
+       if (rdev->gart.ptr) {
+               mb();
+               radeon_gart_tlb_flush(rdev);
+       }
 }
 
 /**
@@ -292,8 +294,10 @@ int radeon_gart_bind(struct radeon_device *rdev, unsigned offset,
                        }
                }
        }
-       mb();
-       radeon_gart_tlb_flush(rdev);
+       if (rdev->gart.ptr) {
+               mb();
+               radeon_gart_tlb_flush(rdev);
+       }
        return 0;
 }