[mythtv] [mythtv-commits] mythtv commit: r26314 - in trunk/mythtv by markk
mark.kendall at gmail.com
Sun Sep 19 04:08:49 UTC 2010
On 15 September 2010 05:19, Mark Spieth <mark at digivation.com.au> wrote:
> On 9/14/2010 5:39 PM, mythtv at cvs.mythtv.org wrote:
>> Disable OpenGL vsync.
>> This has not worked since the OSD merge and despite trying a number of
>> different approaches, I've utterly failed to fix it. I suspect it is due
>> to some interaction with the Qt rendering subsystem, though that doesn't
>> explain why it would fail when using the Qt painter as well as the
>> OpenGL version.
> could you explain what is not working in openglsync?
> seems fine to me but I ma using a few patches from #7964.
> is it while osd is displayed? (again LGTM)
The one consistent symptom I've seen across NVidia, Intel and ATI
linux systems is that the display is not physically synced to the
vertical retrace and hence you still get tearing. No errors are
reported - it just doesn't work. On one system with an older intel
integrated GPU, the sync calls returned without delay and broke
playback. On other systems (mainly ATI and newer intel GPUs), X vomits
error messages at an impressive rate.
The latter error messages are, I'm sure, related to the particular
implementation of the OpenGL vsync code in trunk - it uses a pixmap as
the 'device' to sync to. While this is almost certainly not the
correct approach, I have tried probably a dozen other implementations
and none of these have fixed it either.
As mentioned in the commit, I was however reasonably comfortable
disabling it at this point as I'm pretty confident that 99% of people
simply do not need it. It shouldn't be needed on any non-linux build,
any linux system with an nvidia gpu, intel systems use drm and xvideo
sync to vblank (which is, as far as I'm concerned about the only
supportable playback option on intel). I haven't checked ATI for a
while - mostly because working with ATI/AMD cards is so painful:)
Out of interest, what video renderer and video card combination are you using?
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