On Fri, May 31, 2013 at 8:56 PM, Andy Furniss adf.lists@gmail.com wrote:
Daniel Vetter wrote:
On Fri, May 31, 2013 at 03:23:41PM +0300, ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@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@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.
Yeah, I think this should be useful for a bunch of people. I've recently chatted with a few xbmc folks on #irc and one thing they've requested is mode fine-tuning. For DP we should have plenty of precision, but for HDMI we'd need to (slightly) frob the vtotal ever so often to compensate. With some runtime-tuning a la npt we should have perfect a/v sync without any audio resampling.
Apologies, for jumping in here, but assuming I haven't missed anything you've done already: do you have any plans for supporting CEA interlaced modes?
That's assuming they actually need any more support - I only know that they are slightly wrong for me testing with radeon + my TV - are they tested and known to work / not work on intel hw?
The symptom I get is not instantly obvious - the second half of the bottom line gets rendered and repeated as the top line.
For me the reason that proper support could in theory be useful, is that were there in future a way to sync up properly, my TV will do a nice "free" deinterlace. Even on a fast quad core PC doing one as good on cpu is not possible for HD 50i.
Interlaced modes are supported on all intel platforms (except i8xx, hw can't do it there) and we have full support for CEA modes. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch