Re: [PATCH/RFC 0/4] Implement standard color keying properties

[Dmitry Osipenko <digetx@gmail.com>]

Hello Laurent,

On 17.12.2017 03:17, Laurent Pinchart wrote:
> Hello,
> 
> This patch series is an attempt at implementing standard properties for color
> keying support in the KMS API.

I was looking at implementing colorkey support for NVIDIA Tegra (older Tegra's
in particular) and Daniel Vetter suggested that colorkey should be implemented
as a generic plane property, instead of a custom one that I had in the patch
[0]. I've applied your RFC patch and replaced custom property with the generic,
it works well.

Very likely that all HW should be capable of making pixel completely transparent
when it matches a specified color, that could be one of common modes. Though
there could be limitations, like Tegra's aren't able to do blending-over of
planes if colorkey'ing is enabled. The 'colorkey.mode' property allows driver to
expose both common properties and a custom ones. In case of Tegra we could
implement a common property such that atomic commit will be rejected if planes
blending mode aren't compatible with the enabled colorkey'ing, and have a custom
property for a custom HW-aware application that won't be rejected (for example
Opentegra's Xv extension). The common modes could be derived later, once generic
property will get more usage by a variety of drivers. For now I don't see any
issues with your approach and hope to see this series applied in upstream to get
use of them, please continue your effort.

[0] https://patchwork.kernel.org/patch/10342849/