4.4-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit bb24153a3f13dd0dbc1f8055ad97fe346d598f66 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/video/udlfb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/video/udlfb.h +++ b/include/video/udlfb.h @@ -87,7 +87,7 @@ 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 */