drm/radeon: clarify why we evict vram twice on suspend

Update the comment to explain why we do this.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index eb92aef..79c9b6f 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1651,7 +1651,10 @@ int radeon_suspend_kms(struct drm_device *dev, bool suspend,
 
        radeon_suspend(rdev);
        radeon_hpd_fini(rdev);
-       /* evict remaining vram memory */
+       /* evict remaining vram memory
+        * This second call to evict vram is to evict the gart page table
+        * using the CPU.
+        */
        radeon_bo_evict_vram(rdev);
 
        radeon_agp_suspend(rdev);