[mythtv] Mythbackend stuffs up if no video signal is present

Isaac Richards ijr at po.cwru.edu
Fri May 9 03:04:40 EDT 2003


On Friday 09 May 2003 01:02 am, Ron Aldrich wrote:
> Folks,
>
> Over the past couple of weeks, I've been trying to track down an
> intermittent lockup where Mythbackend stuffs up in
> RequestRingBufferBlock, causing Mythfrontend to lock up waiting for
> video.
>
> It turns out that after my RCA DSS receiver sits long enough, it takes
> it upon itself to turn off the video - then, then next time I select
> 'Watch TV', in Mythfrontend, it locks up (before opening the video
> window) because there is no video (I'm currently testing a temporary
> fix for this where I issue an 'on' code in RCA.pl before each channel
> change).
>
> I should mention that I'm using a PVR-350 card for my video input - the
> ivtv drivers don't generate an output stream unless there is a video
> signal.
>
> I'm not sure what the right solution is for this - I'd like to see a
> "no video signal detected" screen in Mythfrontend, but I'm not sure
> where it should be generated.  Ivtv could generate it, but then ivtv
> would have to be localizable, and Mythbackend would have no way to know
> whether or not it is receiving a valid data stream.  I'm thinking that
> ivtv should report I/O errors, and mythbackend should then fabricate an
> appropriate data stream for Mythfrontend.

Until there's a way to get signal status from the driver (support for this 
exists in v4l, but is not to my knowledge implemented in the ivtv driver), 
there's not really all that much I can do about it.

Isaac


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