drm/amdgpu: 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/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 9df66d1e843d111fe945fa588c50d6eda0065e13..afeb7ab16d09b456564aac1ee15c90b49c336be1 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1982,7 +1982,10 @@ int amdgpu_device_suspend(struct drm_device *dev, bool suspend, bool fbcon)
 
        r = amdgpu_suspend(adev);
 
-       /* evict remaining vram memory */
+       /* evict remaining vram memory
+        * This second call to evict vram is to evict the gart page table
+        * using the CPU.
+        */
        amdgpu_bo_evict_vram(adev);
 
        pci_save_state(dev->pdev);