aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMikulas Patocka <mpatocka@redhat.com>2018-07-25 15:41:55 +0200
committerBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>2018-07-25 15:41:55 +0200
commitbb24153a3f13dd0dbc1f8055ad97fe346d598f66 (patch)
treefbb89099971839d4da3fd909d0425ca9c6141942
parent2c29cfc3eaf11779176bf41475cfca49bccba11c (diff)
downloadlinux-stericsson-bb24153a3f13dd0dbc1f8055ad97fe346d598f66.tar.gz
udlfb: set optimal write delay
The default delay 5 jiffies is too much when the kernel is compiled with HZ=100 - it results in jumpy cursor in Xwindow. In order to find out the optimal delay, I benchmarked the driver on 1280x720x30fps video. I found out that with HZ=1000, 10ms is acceptable, but with HZ=250 or HZ=300, we need 4ms, so that the video is played without any frame skips. This patch changes the delay to this value. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
-rw-r--r--include/video/udlfb.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/video/udlfb.h b/include/video/udlfb.h
index b4f43d3ac1af..6e1a2e790b1b 100644
--- a/include/video/udlfb.h
+++ b/include/video/udlfb.h
@@ -88,7 +88,7 @@ struct dlfb_data {
#define MIN_RAW_PIX_BYTES 2
#define MIN_RAW_CMD_BYTES (RAW_HEADER_BYTES + MIN_RAW_PIX_BYTES)
-#define DL_DEFIO_WRITE_DELAY 5 /* fb_deferred_io.delay in jiffies */
+#define DL_DEFIO_WRITE_DELAY msecs_to_jiffies(HZ <= 300 ? 4 : 10) /* optimal value for 720p video */
#define DL_DEFIO_WRITE_DISABLE (HZ*60) /* "disable" with long delay */
/* remove these once align.h patch is taken into kernel */