Re: [RFC PATCH] HDMI:Support for EDID parsing in kernel.

[Dave Airlie <airlied@gmail.com>]

On Wed, Mar 23, 2011 at 3:32 AM, Mythri P K <mythripk@ti.com> wrote:
> Adding support for common EDID parsing in kernel.
>
> EDID - Extended display identification data is a data structure provided by
> a digital display to describe its capabilities to a video source, This a
> standard supported by CEA and VESA.
>
> There are several custom implementations for parsing EDID in kernel, some
> of them are present in fbmon.c, drm_edid.c, sh_mobile_hdmi.c, Ideally
> parsing of EDID should be done in a library, which is agnostic of the
> framework (V4l2, DRM, FB)  which is using the functionality, just based on
> the raw EDID pointer with size/segment information.
>
> With other RFC's such as the one below, which tries to standardize HDMI API's
> It would be better to have a common EDID code in one place.It also helps to
> provide better interoperability with variety of TV/Monitor may be even by
> listing out quirks which might get missed with several custom implementation
> of EDID.
> http://permalink.gmane.org/gmane.linux.drivers.video-input-infrastructure/30401
>
> This patch tries to add functions to parse some portion EDID (detailed timing,
> monitor limits, AV delay information, deep color mode support, Audio and VSDB)
> If we can align on this library approach i can enhance this library to parse
> other blocks and probably we could also add quirks from other implementation
> as well.
>

If you want to take this approach, you need to start from the DRM EDID parser,
its the most well tested and I can guarantee its been plugged into more monitors
than any of the others. There is just no way we would move the DRM parser to a
library one that isn't derived from it + enhancements, as we'd throw away the
years of testing and the regression count would be way too high.

Dave.