From: Michel Dänzer <michel.daenzer@amd.com>
Date: Fri, 3 Jul 2015 01:02:27 +0000 (+0900)
Subject: drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL
X-Git-Tag: v3.16.35~1609
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fd6139cf4a55d889063c3894938bf672511c6ef5;p=thirdparty%2Fkernel%2Fstable.git

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 2e723651069bd..4259a1fa323f5 100644
--- 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;
 }