Hi Jesse, On Wed, Mar 23, 2011 at 8:48 PM, Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> wrote: > On Wed, 23 Mar 2011 18:58:27 +0530 > "K, Mythri P" <mythripk@xxxxxx> wrote: > >> Hi Dave, >> >> On Wed, Mar 23, 2011 at 6:16 AM, Dave Airlie <airlied@xxxxxxxxx> wrote: >> > On Wed, Mar 23, 2011 at 3:32 AM, Mythri P K <mythripk@xxxxxx> 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. > > If that's the only issue you have, we could easily rename that > structure or add conversion funcs to a smaller structure if that's what > you need. > > Dave's point is that we can't ditch the existing code without > introducing a lot of risk; it would be better to start a library-ized > EDID codebase from the most complete one we have already, i.e. the DRM > EDID code. > This sounds good. If we can remove the DRM dependent portion to have a library-ized EDID code, That would be perfect. The main Intention to have a library is, Instead of having several different Implementation in kernel, all doing the same EDID parsing , if we could have one single implementation , it would help in better testing and interoperability. > Do you really think the differences between your code and the existing > DRM code are irreconcilable? > On the contrary if there is a library-ized EDID parsing using the drm_edid, and there is any delta / fields( Parsing the video block in CEA extension for Short Video Descriptor, Vendor block for AV delay /Deep color information etc) that are parsed with the RFC i posted i would be happy to add. Thanks and regards, Mythri. > -- > Jesse Barnes, Intel Open Source Technology Center > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
