Dear Uli, Dear Laurent, Dear Renesas community, On Mo, Mai 30, 2016 at 06:00:13 +0200, Ulrich Hecht wrote: > This patch changes to VSPD hardware recommended value. > Purpose is highest pixel clock without underruns. > In the default R-Car Linux BSP config this value is > wrong and therefore there are many underruns. > > Signed-off-by: Takashi Saito <takashi.saitou.ry@xxxxxxxxxxx> > Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@xxxxxxxxxxx> > Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@xxxxxxxxx> > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > --- > drivers/media/platform/vsp1/vsp1_lif.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) Apologize for reviving this very old thread. We've been struggling with very rare and difficult to reproduce display flickering occurrences and, after significant amount of troubleshooting and debugging, with some support from Renesas, we've been able to identify that those flicker issues are caused by VSPD underruns. What we've also learned is that one possible root-cause for seeing VSPD underruns is having wrong QoS settings in DBSC (set in ATF). What was particularly helpful in identifying the underruns themselves is Renesas BSP commit [1], whose discussions we were unable to track on linux-renesas-soc LKML. My question is very simple. Since the meat of the Renesas patch [1] is basically a printk in the interrupt context and an array storing the total number of underruns occurred since startup, would you be willing to review the refactored version of this patch on LKML? In that case, we'll definitely invest some time to upstream it. Thank you for your attention and feedback. [1] https://github.com/renesas-rcar/linux-bsp/commit/12ea79975a10f ("v4l: vsp1: Add underrun debug messege option") Best regards, Eugeniu
