imx8mm lcdif->dsi->adv7535 no video, no errors

Marco Felsch m.felsch at pengutronix.de
Tue Aug 2 08:08:20 UTC 2022


Hi Adam, Fabio,

On 22-08-01, Adam Ford wrote:
> On Mon, Aug 1, 2022 at 8:53 PM Fabio Estevam <festevam at gmail.com> wrote:
> >
> > On Mon, Aug 1, 2022 at 10:39 PM Adam Ford <aford173 at gmail.com> wrote:
> >
> > > I managed to get my HDMI output working. I had the lanes set to 2
> > > instead of 4.  Once I switched to 4-lanes, the monitor came up in
> > > 1080p.  I haven't yet been able to get other modes to work.
> >
> > Ok, good. On another thread, you mentioned that you were also trying
> > to get LVDS to work via SN65DSI83.
> >
> > Does LVDS work for you on this branch?
> 
> I haven't tried with Marek's latest suggestion.  In the other thread
> he mentioned a burst mode and setting the DSI speeds to higher
> frequencies, but the patch he had didn't look like it would apply
> cleanly, so I will need to dig into that a bit further. 

Can you provide me a link to this thread?

> Since my company doesn't really ship the LVDS displays with the kits,
> the HDMI is the default video, so I've been focusing on it.
> 
> To answer Marco's question, I was able to revert "MLK-21958-13:
> drm/bridge: adv7511: Limit supported clocks" and still get a display
> at 1080p, but all the other resolutions I tried appear to come up
> blank. 

Cool so now you have the same state as we are.

I think that the most important one is the blanking calc. Can you try to
revert "drm/bridge: adv7511: Repair bus_flags and bus_format" and check
if you can get a output still? Also something to try would be to disable
the internal timing generator by specifying
'adi,disable-timing-generator'. Also if you have an oscilloscope for
such frequencies you can check the hdmi clk-lane. I noticed that this is
sometimes wrong.

Regards,
  Marco

> I didn't try every one.  With that revert, more options come
> available, but 1440x900 and 800x600 were options I tried
> unsuccessfullyl.

> 
> adam
> 


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