Hello,
On Monday 16 March 2015 09:06:22 Geert Uytterhoeven wrote:
> On Sun, Mar 15, 2015 at 3:33 PM, Yoshihiro Kaneko wrote:
> > From: Yoshifumi Hosoya <yoshifumi.hosoya.wj@xxxxxxxxxxx>
> >
> > Change 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.
> >
> > Here are the original settings:
> > HBTH = 1300 (VSPD stops when 1300 pixels are buffered)
> > LBTH = 200 (VSPD resumes when buffer level has decreased
> > below 200 pixels)
> >
> > The display underruns can be eliminated
> > by applying the following settings:
> > HBTH = 1504
> > LBTH = 1248
> >
> > --- a/drivers/media/platform/vsp1/vsp1_lif.c
> > +++ b/drivers/media/platform/vsp1/vsp1_lif.c
> > @@ -44,9 +44,9 @@ static int lif_s_stream(struct v4l2_subdev *subdev, int
> > enable)
> > {
> > const struct v4l2_mbus_framefmt *format;
> > struct vsp1_lif *lif = to_lif(subdev);
> > - unsigned int hbth = 1300;
> > - unsigned int obth = 400;
> > - unsigned int lbth = 200;
> > + unsigned int hbth = 1536;
> > + unsigned int obth = 128;
> > + unsigned int lbth = 1520;
>
> These values don't match the patch description?
Indeed. And where do these values come from ? A 16 bytes hysteresis is very
small, the VSP1 will constantly start and stop. Isn't that bad from a power
consumption point of view ?
> BTW, what's the significance of changing obth?
--
Regards,
Laurent Pinchart
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