Re: [PATCH v3 06/13] drm: bridge: Add LVDS encoder driver

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Jan 04, 2017 at 04:33:57PM +0200, Laurent Pinchart wrote:
> On Wednesday 04 Jan 2017 14:51:48 Daniel Vetter wrote:
> > Hm, something like drm_bridge_panel_bridge_init(dev, panel) should be
> > enough, or not? My idea is to use this for the case where the only
> > thing in dt is the panel, with no real bridge chip. And I think we
> > don't need anything beyond that one _init function, plus maybe some
> > additional paramaters ...
> 
> There should be no bridge then. If you want the DRM core to manage panels 
> automatically, then we should create specific helpers for that, not abuse the 
> bridge infrastructure. Bridges should be instantiated from a hardware device 
> and bound to drivers as usual.

I guess that's the part where I disagree: Just because there's physically
no bridge doesn't mean we shouldn't just treat it as one in the software
abstraction. If it looks and acts like a bridge (even an empty one), then
imo it can be a bridge.

If you insist on panels being panels, then I guess we need some other kind
of glue to bind them into arbitrary bridge chains. But given that the
callbacks match very closely, I don't see the point.

In an idea world a panel would probably derive from a drm_bridge, but
we're not in that universe unfortunately ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch