On Thu, 24 Mar 2011, K, Mythri P wrote: > 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. Does the DRM EDID-parser also process blocks beyond the first one and also parses SVD entries similar to what I've recently added to fbdev? Yes, we definitely need a common EDID parses, and maybe we'll have to collect various pieces from different implementations. Thanks Guennadi > > > 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 > --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- 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
