On Wed, May 25, 2016 at 07:55:23PM +0000, Yang, Eric wrote:
> Hi Thierry Reding,
>
> enum hdmi_picture_aspect {
> > HDMI_PICTURE_ASPECT_NONE,
> > HDMI_PICTURE_ASPECT_4_3,
> > HDMI_PICTURE_ASPECT_16_9,
> > + HDMI_PICTURE_ASPECT_64_27,
> > + HDMI_PICTURE_ASPECT_256_135,
> > HDMI_PICTURE_ASPECT_RESERVED,
> > };
>
> These are defined since CEA861F defines them in section 4.1.
> However, it is not indicated in AVI InfoFrame definition for picture aspect
> ratio (M1,M0), and we should indicate (M1,M0) = (0,0) for "No Data" when
> sending VICs corresponding to these new aspect ratios.
>
> If (M1,M0) = (0,0) "No Data" is indicated, then If M=0 (M1=0, M0=0) and
> VIC=0, a Sink shall assume the Picture is formatted according to the
> Preferred Picture Aspect Ratio.
>
> The defition:
>
> Preferred Picture Aspect Ratio-In a Dual-Aspect Ratio DTV, the preferred
> aspect ratio of a given Video Format Timing (e.g., 720x480p) is the aspect
> ratio of the first such timing listed in the EDID data structure (see Section
> 4.1). This would be the Picture Aspect Ratio that would be displayed if a DTV
> were to receive a Video Format Timing with no accompanying Picture Aspect
> Ratio information (i.e., no AVI sent from Source).
>
> Alternatively, since our code does not actively use
> HDMI_PICTURE_ASPECT_64_27, HDMI_PICTURE_ASPECT_256_135, we can unify them as
> HDMI_PICTURE_ASPECT_NONE, and send (M1,M0) = (0,0) to avoid confusion.
There's already drm core patches to add all this stuff for the new aspect
ratios:
https://patchwork.freedesktop.org/series/4896/
Would be great if you can review them. Patch 5 of that series (for
i915.ko) needs to be polished a bit, but the other bits all look fine to
me at a quick glance.
Thanks, Daniel
>
>
>
> -----Original Message-----
> From: Thierry Reding <thierry.reding at gmail.com>
> Sent: Friday, May 13, 2016 11:28:39 AM
> To: Yang, Eric
> Cc: dri-devel at lists.freedesktop.org; linux-fbdev at vger.kernel.org;
> tomi.valkeinen at ti.com; plagnioj at jcrosoft.com
> Subject: Re: [PATCH] drm: expand cea861 mode timing table
>
> On Thu, May 12, 2016 at 03:37:33PM -0400, Eric Yang wrote:
> [...]
> > diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h index
> > e974420..edbb4fc 100644
> > --- a/include/linux/hdmi.h
> > +++ b/include/linux/hdmi.h
> > @@ -78,6 +78,8 @@ enum hdmi_picture_aspect {
> > HDMI_PICTURE_ASPECT_NONE,
> > HDMI_PICTURE_ASPECT_4_3,
> > HDMI_PICTURE_ASPECT_16_9,
> > + HDMI_PICTURE_ASPECT_64_27,
> > + HDMI_PICTURE_ASPECT_256_135,
> > HDMI_PICTURE_ASPECT_RESERVED,
> > };
>
> Where did you get these from? I'm asking because I sent this patch last year
> (or at least I wrote it and we discussed it on IRC, since I can't find an
> email archive link to it), and back at the time the picture aspect ratio was
> the big question mark. My recollection is that CEA-861-F introduces these new
> picture aspect ratios in the mode tables but never specifies their values. As
> a matter of fact, the AVI infoframe where these values are used only has
> space for 4 values (none, 4:3, 16:9 and reserved).
>
> Would you mind pointing me at the specification for these values?
>
> Thanks,
> Thierry
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
