[PATCH] drm/edid: Add both 60Hz and 59.94Hz CEA modes to connector's mode list

Ville Syrjälä ville.syrjala at linux.intel.com
Tue Jun 18 03:30:33 PDT 2013


On Tue, Jun 18, 2013 at 11:10:30AM +0100, Andy Furniss wrote:
> ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >
> > Having both modes can be beneficial for video playback cases. If you can
> > match the video framerate exactly, and the audio and video clocks come
> > from the same source, you should be able to avoid dropped/repeated
> > frames without expensive operations such as resampling the audio to
> > match video output rate.
> >
> > Rather than add both variants based on the CEA extension short video
> > descriptors in do_cea_modes(), add only one variant there. Once all
> > the EDID has been fully probed, do a loop over the entire probed mode
> > list, during which we add the other variants for all modes that match
> > CEA modes. This allows us to match modes that didn't come via the CEA
> > short video descriptors. For example one Samsung TV here doesn't have
> > the 640x480-60 mode as a SVD, but instead it's specified via a detailed
> > timing descriptor.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> > A few people requested this. Originally I was a bit opposed to it, but
> > when I thought about it a bit more I figured if the audio and video
> > clocks come from the same source (or happen to be close enough w/o
> > significant drift), this could provide a better A/V sync w/o resampling
> > tricks.
> 
> I see this has gone in now, one thing I notice is that xorg/apps/xrandr 
> only prints Hz to 1dp so you can't see which mode is which for the 24p 
> and 30i cases.
> 
> Maybe someone reading has commit access for xorg?

Not sure if you noticed but I posted some relevant xrandr patches to
xorg-devel. Unfortunately I got no response, and I've been too lazy
to figure out who I need to pester.

-- 
Ville Syrjälä
Intel OTC


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