Re: DSI panel not working on -next

[Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

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On Fri, Feb 13, 2015 at 03:29:09PM +0900, Alexandre Courbot wrote:
> Hi Thierry,
> 
> I noticed that the DSI panel of SHIELD (tegra114-roth) was not brought up on
> -next. I have bisected the following commit as introducing that behavior:
> 
> commit f4c5cf88fbd50e4779042268947b2e2f90c20484
> Author: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> Date:   Thu Dec 18 15:29:14 2014 +0100
> 
>     gpu: host1x: Provide a proper struct bus_type
> 
> 
> With and without this patch, the DSI panel is probed, but the stack trace in
> the probe() function is different:

This shouldn't make much of a difference, really, since we're attaching
to the panel only during mipi_dsi_host_register() anyway. And the panel
device can't exist earlier than that because mipi_dsi_host_register()
will instantiate it. Still...

> i.e. with f4c5cf88fbd, the panel is not probed from tegra_dsi_probe()
> anymore, which means DSI remains without a valid connector:
> 
> [    1.378513] [drm] Initialized drm 1.1.0 20060810
> [    1.384564] 54300000.dsi supply avdd-dsi-csi not found, using dummy
> regulator
> [    1.396394] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> [    1.403021] [drm] No driver support for vblank timestamp query.
> [    1.409080] drm drm: No connectors reported connected with modes
> [    1.415128] [drm] Cannot find any crtc or sizes - going 1024x768

... the failing log here does indicate that there is no panel, so I'll
need to investigate why that's happening.

> Are you aware of this? Does it affect other DSI panels? Does SHIELD's DT
> need an update of some sort?

I'm almost certain that I've tested this on at least Dalmore and I don't
see any differences that could be causing this. I'll look into it.

Thierry

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