How to support various hardware blocks in drm driver

[Inki Dae]

2014-03-18 21:22 GMT+09:00 Daniel Vetter <daniel at ffwll.ch>:
> On Tue, Mar 18, 2014 at 1:12 PM, Rob Clark <robdclark at gmail.com> wrote:
>> I think the question is how to go from zero or one
>> bridge/hwblock/widget/whatever to zero or more..
>>
>> an alternate set of helpers is one option.  But it didn't turn out to
>> be too intrusive to the existing helpers to add bridge in the first
>> place, so I'm not sure it will be necessary.
>
> I guess we could allow bridges to chain up and have multiple
> child-bridges or something like that. Plus a helper which finds a
> suitable routing through this network (it should be a tree after all,
> so no ambiguity) given a drm_connector/drm_encoder pair. Or maybe I
> misunderstand what you mean by going from 1 bridge to multiple bridges
> ...

Daniel,

I think now drm_bridge couldn't do what we want for embedded systems
as long as drm_encoder has drm_bridge.
See the blow hardware pipeline,
Display Controller-----Image Enhancement chip-----MIP DSI-----MIPI TO
LVDS Bridge-----LCD Panel

In above hardware pipeline, Display controller is controlled by crtc,
and Image Enhancement chip receives output from display controller.
So the use of existing drm_bridge would be suitable to only bridge
devices between MIPI DSI and LCD Panel, but not to Image Enhancement
chip.

For such hardware, drm_panel infrastructure is more reasonable to me,
and that is why I try to integrate drm_panel and drm_bridge to one
integrated framework which has infrastructure same as existing
drm_panel.
The important thing is to free this integrated framework from
drm_encoder so that crtc device can also use this framework.

Thanks,
Inki Dae

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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