[PATCH 02/21] drm: mxsfb: Use drm_panel_bridge

[Sam Ravnborg]

Hi Stefan.

On Mon, Mar 23, 2020 at 10:27:21PM +0100, Stefan Agner wrote:
> On 2020-03-09 20:51, Laurent Pinchart wrote:
> > Replace the manual connector implementation based on drm_panel with the
> > drm_panel_bridge helper. This simplifies the mxsfb driver by removing
> > connector-related code, and standardizing all pipeline control
> > operations on bridges.
> > 
> > A hack is needed to get hold of the connector, as that's our only source
> > of bus flags and formats for now. As soon as the bridge API provides us
> > with that information this can be fixed.
> 
> This seems like a nice simplification.
> 
> I gave this a go applied on today's drm-misc-next using a Colibri iMX7
> (imx7d-colibri-emmc-eval-v3.dts device tree). This device makes use of
> the simple panel driver. I get this when booting:
> 
> [    2.976698] [drm] Supports vblank timestamp caching Rev 2
> (21.10.2013).
> [    2.983526] ------------[ cut here ]------------
> [    2.988180] WARNING: CPU: 0 PID: 1 at
> drivers/gpu/drm/bridge/panel.c:267 devm_drm_panel_bridge_add+0x25/0x28

...

I think you hit one of the panels that does not yet specify a
connector_type.

If this is the case, we should fix the definition in panel-simple.

	Sam