[PATCH 1/2] drm/amdgpu: Add comment to function amdgpu_ttm_alloc_gart

[Oak Zeng]

Add comments to refect what function does

Signed-off-by: Oak Zeng <Oak.Zeng at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 63e5414..8b70445 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1210,7 +1210,12 @@ static int amdgpu_ttm_backend_bind(struct ttm_tt *ttm,
 }
 
 /**
- * amdgpu_ttm_alloc_gart - Allocate GART memory for buffer object
+ * amdgpu_ttm_alloc_gart - Make sure buffer object is accessible either
+ * through AGP or GART aperture.
+ *
+ * If bo is accessible through AGP aperture, then use AGP aperture
+ * to access bo; otherwise allocate logical space in GART aperture
+ * and map bo to GART aperture.
  */
 int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
 {
-- 
2.7.4