[linux-dvb] Re: Using new driver with DVB-T

[Mike Grant <mgg@ecs.soton.ac.uk>]

Just adding myself to the list of people who've experienced slowdowns 
that are apparently due to the kdvb-fe threads.  I spent the weekend 
trying to isolate the cause of some glitches I've been experiencing 
recently and I'm fairly confident I can pin the blame on the kdvb-fe 
threads.

I've got a Celeron-450 with a DVB-S and a DVB-T.  If I load up the 
drivers, _don't_ tune either card and then play a known-good mpg2 file 
with ntuxplayer (the most lightweight DVB-S player I could find), I get 
sound glitches during playback.  Each kdvb-fe thread is eating ~35% CPU 
(albeit idle time) - totalling 69% CPU.  If I load the driver, but 
without the DVB-S tuner module, then tune the DVB-T to some channel, I 
have one kdvb-fe thread at ~3% CPU and perfect playback.

I speculate that the kdvb-fe threads cause enough latency to make the 
rest of the system just a little too slow to maintain sufficient throughput.

The problem I have is that my DVB-S card is purely for (vdr) output, so 
it's never tuned - it's not even got a dish connected.  Consequently, 
with the default driver load, I always have one kdvb-fe burning ~35% CPU.

While my solution of not loading the DVB-S tuner is an adequate 
workaround, perhaps it'd be better to not activate the zigzag scan when 
the driver first loads since any cards present are unlikely to be tuned 
to a valid channel.  Once a tuning has been made, then activate the 
zigzag scan.

Regards,

Mike Grant.



-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe linux-dvb" as subject.