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.
-----Original Message-----
From: Thierry Reding <thierry.red...@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
