[PATCH 4/8] drm/ast: Pin framebuffer BO during dirty update

[Thomas Zimmermann]

Another explicit lock operation of a GEM VRAM BO is located in AST's
framebuffer update code. Instead of locking the BO, we pin it to wherever
it is.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/ast/ast_fb.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
index 05f45222b702..7d911391c9cf 100644
--- a/drivers/gpu/drm/ast/ast_fb.c
+++ b/drivers/gpu/drm/ast/ast_fb.c
@@ -48,32 +48,32 @@ static void ast_dirty_update(struct ast_fbdev *afbdev,
 			     int x, int y, int width, int height)
 {
 	int i;
-	struct drm_gem_object *obj;
 	struct drm_gem_vram_object *gbo;
 	int src_offset, dst_offset;
 	int bpp = afbdev->afb.base.format->cpp[0];
-	int ret = -EBUSY;
+	int ret;
 	u8 *dst;
 	bool unmap = false;
 	bool store_for_later = false;
 	int x2, y2;
 	unsigned long flags;
 
-	obj = afbdev->afb.obj;
-	gbo = drm_gem_vram_of_gem(obj);
+	gbo = drm_gem_vram_of_gem(afbdev->afb.obj);
 
-	/* Try to lock the BO. If we fail with -EBUSY then
-	 * the BO is being moved and we should store up the
-	 * damage until later.
+	/* We pin the BO to system memory so it won't be moved during
+	 * the update and doesn't waste video ram. If the BO is already
+	 * located in VRAM, the pin operation will simply increment the
+	 * pin count.
 	 */
-	if (drm_can_sleep())
-		ret = drm_gem_vram_lock(gbo, true);
-	if (ret) {
-		if (ret != -EBUSY)
-			return;
-
+	if (drm_can_sleep()) {
+		ret = drm_gem_vram_pin(gbo, TTM_PL_FLAG_SYSTEM);
+		if (ret) {
+			if (ret != -EBUSY)
+				return;
+			store_for_later = true;
+		}
+	} else
 		store_for_later = true;
-	}
 
 	x2 = x + width - 1;
 	y2 = y + height - 1;
@@ -126,7 +126,7 @@ static void ast_dirty_update(struct ast_fbdev *afbdev,
 		drm_gem_vram_kunmap(gbo);
 
 out:
-	drm_gem_vram_unlock(gbo);
+	drm_gem_vram_unpin(gbo);
 }
 
 static void ast_fillrect(struct fb_info *info,
-- 
2.21.0