RE: [PATCH v3 2/5] drm: xlnx: zynqmp_dpsub: Fix timing for live mode

[Klymenko, Anatoliy]

Hi Laurent,

Thanks a lot for the review.

> -----Original Message-----
> From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Sent: Monday, February 5, 2024 12:08 AM
> To: Klymenko, Anatoliy <Anatoliy.Klymenko@xxxxxxx>
> Cc: maarten.lankhorst@xxxxxxxxxxxxxxx; mripard@xxxxxxxxxx;
> tzimmermann@xxxxxxx; airlied@xxxxxxxxx; daniel@xxxxxxxx; Simek, Michal
> <michal.simek@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 2/5] drm: xlnx: zynqmp_dpsub: Fix timing for live mode
> 
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> 
> 
> Hi Anatoliy,
> 
> Thank you for the patch.
> 
> On Tue, Jan 23, 2024 at 06:53:59PM -0800, Anatoliy Klymenko wrote:
> > Expect external video timing in live video input mode, program DPSUB
> > acordingly.
> 
> Are there no designs where the DPSUB operates in non-live mode, but uses a
> video clock from the PL, for instance to use a different clock frequency ?
> 
> I don't think that use case is very common, so I'm fine with this patch in order to
> properly support the more common use case of live input, and leave the PL clock
> without live input use case for later.
> 
Theoretically, we can create such a design, but it wouldn't make too much sense since the PS clock is the best choice here. Probably, in some complicated scenarios like hybrid live-in/DMA or live-out, we would consider using the PL video clock, but the DPSUB driver is not supporting them yet.
> >
> > Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> >
> 
> No need for a blank line here.
> 
Sure, I'll fix this in the new version. Thank you.
> > Signed-off-by: Anatoliy Klymenko <anatoliy.klymenko@xxxxxxx>
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> 
> > ---
> >  drivers/gpu/drm/xlnx/zynqmp_disp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c
> > b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> > index 407bc07cec69..8a39b3accce5 100644
> > --- a/drivers/gpu/drm/xlnx/zynqmp_disp.c
> > +++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> > @@ -1166,7 +1166,7 @@ void zynqmp_disp_enable(struct zynqmp_disp *disp)
> >       /* Choose clock source based on the DT clock handle. */
> >       zynqmp_disp_avbuf_set_clocks_sources(disp, disp->dpsub-
> >vid_clk_from_ps,
> >                                            disp->dpsub->aud_clk_from_ps,
> > -                                          true);
> > +
> > + disp->dpsub->vid_clk_from_ps);
> >       zynqmp_disp_avbuf_enable_channels(disp);
> >       zynqmp_disp_avbuf_enable_audio(disp);
> >
> 
> --
> Regards,
> 
> Laurent Pinchart