Re: [PATCH v3 6/7] video: Only dcache flush damaged lines

On 12/30/22 20:58, Alexander Graf wrote:

Now that we have a damage area tells us which parts of the frame buffer actually need updating, let's only dcache flush those on video_sync() calls. With this optimization in place, frame buffer updates - especially on large screen such as 4k displays - speed up significantly.

Signed-off-by: Alexander Graf agraf@csgraf.de Reported-by: Da Xue da@libre.computer

---

v1 -> v2:

• Fix dcache range; we were flushing too much before
• Remove ifdefs

---

drivers/video/video-uclass.c | 51 ++++++++++++++++++++++++++++++------ 1 file changed, 43 insertions(+), 8 deletions(-)

diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c index f1fbeaadcb..bf93f524c7 100644 --- a/drivers/video/video-uclass.c +++ b/drivers/video/video-uclass.c @@ -297,9 +297,45 @@ int video_damage(struct udevice *vid, int x, int y, int width, int height) return 0; }

+#if defined(CONFIG_ARM) && !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)

ARM isn't the only architecture implementing flush_dcache_range(). So this condition needs to be fixed as well as the one in video_sync.

Why don't you simply rely on priv->flash_dcache irrespective of the architecture? Let the video drivers decide if they need it.

Best regards

Heinrich

+static void video_flush_dcache(struct udevice *vid) +{

• struct video_priv *priv = dev_get_uclass_priv(vid);
• if (!priv->flush_dcache)

• return;
  

• if (!CONFIG_IS_ENABLED(VIDEO_DAMAGE)) {

• flush_dcache_range((ulong)priv->fb,
  

• 		   ALIGN((ulong)priv->fb + priv->fb_size,
  

• 			 CONFIG_SYS_CACHELINE_SIZE));
  

• return;
  

• }
• if (priv->damage.endx && priv->damage.endy) {

• int lstart = priv->damage.x * VNBYTES(priv->bpix);
  

• int lend = priv->damage.endx * VNBYTES(priv->bpix);
  

• int y;
  

• for (y = priv->damage.y; y < priv->damage.endy; y++) {
  

• 	ulong fb = (ulong)priv->fb;
  

• 	ulong start = fb + (y * priv->line_length) + lstart;
  

• 	ulong end = start + lend - lstart;
  

• 	start = ALIGN_DOWN(start, CONFIG_SYS_CACHELINE_SIZE);
  

• 	end = ALIGN(end, CONFIG_SYS_CACHELINE_SIZE);
  

• 	flush_dcache_range(start, end);
  

• }
  

• }

+} +#endif

• /* Flush video activity to the caches */ int video_sync(struct udevice *vid, bool force) {
• struct video_priv *priv = dev_get_uclass_priv(vid); struct video_ops *ops = video_get_ops(vid); int ret;

@@ -315,15 +351,8 @@ int video_sync(struct udevice *vid, bool force) * out whether it exists? For now, ARM is safe. */ #if defined(CONFIG_ARM) && !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)

• struct video_priv *priv = dev_get_uclass_priv(vid);
• if (priv->flush_dcache) {

• flush_dcache_range((ulong)priv->fb,
  

• 		   ALIGN((ulong)priv->fb + priv->fb_size,
  

• 			 CONFIG_SYS_CACHELINE_SIZE));
  

• }

• video_flush_dcache(vid); #elif defined(CONFIG_VIDEO_SANDBOX_SDL)

• struct video_priv *priv = dev_get_uclass_priv(vid); static ulong last_sync;

  if (force || get_timer(last_sync) > 100) {

@@ -331,6 +360,12 @@ int video_sync(struct udevice *vid, bool force) last_sync = get_timer(0); } #endif

• if (CONFIG_IS_ENABLED(VIDEO_DAMAGE)) {

• priv->damage.endx = 0;
  

• priv->damage.endy = 0;
  

• }
• return 0; }