Hi Tomi,
On Wed, Nov 27, 2024 at 10:28 AM Tomi Valkeinen
<tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx> wrote:
> On 18/10/2024 12:32, Geert Uytterhoeven wrote:
>
> > White Hawk CN15
> > ---------------
> >
> > Does not work:
> > - Display resolution is detected correctly (1920x1080 or 2560x1440),
> > - Black screen, displays say no signal detected,
> > - "modetest -M rcar-du -s 88:1920x1080@XR24" triggers:
> >
> > rcar-mipi-dsi fed90000.dsi-encoder: Failed to disable video transmission
> > vsp1 fea20000.vsp: Underrun occurred at WPF0 (total underruns 2)
> >
> > Note that fea20000.vsp is vspd0, not vspd1. I do have a few similar
> > messages for fea28000.vsp in my logs, so this may be a red herring.
>
> I had a try with this. The first issue I hit was that ti-sn65dsi86
> driver doesn't work if there are two sn65dsi86 devices: Creating aux
> devices try to create sysfs files with the same names for both devices,
> thus failing. I take you didn't see this?
I did, cfr. my comment in [PATCH/RFC 1/1][2]:
This has a hard dependency on "[PATCH] drm/bridge: ti-sn65dsi86: Fix
multiple instances"[1]
> I brute forced my way through that by doing "aux->id = s_foo++;" in
> ti_sn65dsi86_add_aux_device().
>
> After that, I was in the same situation as you, black screen. The
> ti-sn65dsi86 does detect the monitor, though, and reads the edid just
> fine, so I think it unlikely that the issue is on ti-sn65dsi86 side. I'm
> not sure if the second DSI output has ever been tested, maybe the issue
> is around there.
>
> I did not see the errors you saw. Random underflows are know to happen,
> though, but it's odd if you see them for the display path that's
> (supposedly) not in use...
>
> The fps looks fine, so the pclk and timings are probably ok:
Thanks! So it probably is an issue with the routing in the DU or
DSI driver...
[1] https://lore.kernel.org/8c2df6a903f87d4932586b25f1d3bd548fe8e6d1.1729180470.git.geert+renesas@xxxxxxxxx/
[2] https://lore.kernel.org/all/05e43f61321b4191d5f97dec2349facd4b56c899.1729240989.git.geert+renesas@xxxxxxxxx/
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
