[vdr] Re: maybe temporary solution for using dvb-s+analogtv without dish

[Gregor Lawatscheck <gpel@mpex.net>]

Forgive me for cross-posting but I think it's worth it, as there were 
threads about this on linux-dvb as well. Replies to this Discussion about 
the driver / firmware of the av711x should probably be done on linux-dvb.

At 17:27 28/06/2003, Guido Fiala wrote:
> Hallo,
>
> i tried a lot of combinations of drivers, firmware and lot's of snapshots
> which are supposed to be stable but could'nt find one that works
> stable.
>
> All do crash with ARM-Crash, even commenting out part's of the code
> of the driver that could be responsible did'nt help ...
>
> That's why i did a backport of current vdr to the old stable 0.9.4-driver.
>
> It just requires the dvbdevice.h+.c file from the old vdr with minimal
> changes, in case someone with the same setup like me like to try it:
>
> http://www.s.netic.de/gfiala/vdr-backport-0.9.4driver.tgz
Very nice work. I had always wanted to do something along these lines when 
I pulled my hair out over crashes of the new head driver / firmware. 
Fortunatley I have a pretty stable setup at the moment with the current 
firmware's larger video memory and a stable signal on the DVB-s. Obviously 
it'd be great to get this fixed or worked around in the current driver / 
firmware.

I believe the root problem lies in the firmware. Without a signal or a bad 
signal on the full featured card over time there appears to be some kind of 
video memory / overflow memory depletion without memory being flushed 
properly. With a bad signal this memory depletion can be achieved fairly 
quickly (within a couple of minutes). If there is no signal at all the 
depletion seems to take up to around four hours. The result is that when 
feeding data to the demux the client buffer fills up to 100% and no 
decoding will be done anymore (as was the case with too little video 
memory). I believe the problem of instability with no signal was introduced 
in the Aug 30 2002 firmware. Maybe someone can confirm this?

If the cause can't be found in the firmware maybe at driver or client level 
one could send infrequent buffer flushes on no / bad primary card signal, 
hoping to keep it stable. Certainly when outcom errors appear it might be a 
good idea to flush the vid memory if at all possible? 


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