Re: [PATCH v4 3/7] drm/tilcdc: Add support for external tda998x encoder

[Jyri Sarha <jsarha@ti.com>]

On 04/02/15 01:20, Russell King - ARM Linux wrote:
> This is where the DRM model is weak - we don't really have a way to
> say "this is the set of CRTCs which/can/  be associated with this
> connector, can any of the CRTCs accept this mode?" and eliminate
> modes which fail that check.
>
> This problem seems to be one which recurrs, so I wonder if it's
> something which ought to be solved properly.
>
> It's made slightly more difficult because we don't really know which
> connectors could be associated with which CRTCs - that information is
> stored at the encoder level (with the encoders possible_crtcs), and
> I'm not sure we have a way for generic DRM code to know which encoders
> could be associated with which connectors.

I agree that this is not the most elegant solution to the problem, but 
it works with Beaglebone-Black - which is AFAIK the only piece of HW 
that uses tda998x with tilcdc.

I would like to get these patches merged and revisit the mode validation 
code once we have a better solution for it.

Best regards,
Jyri