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

K, Mythri P mythripk at ti.com
Wed Mar 23 06:28:27 PDT 2011

Hi Dave,

On Wed, Mar 23, 2011 at 6:16 AM, Dave Airlie <airlied at gmail.com> wrote:
> On Wed, Mar 23, 2011 at 3:32 AM, Mythri P K <mythripk at 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.
I had a look at the DRM EDID code, but for quirks it looks pretty much the same.
yes i could take quirks and other DRM tested code and enhance, but
still the code has to do away with struct drm_display_mode
which is very much custom to DRM.

> Dave.

Thanks and regards,

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