[linux-dvb] Re: Demux stops to work when tuning too many time

[Johannes Stezenbach <js@linuxtv.org>]

Valsecchi Patrick wrote:
> > Can you recover by reloading the drivers, including saa7146?
> > If that doesn't work, can you try to enable the (commented out)
> > master rest in saa7146_core.c?
> > (saa7146_write(dev, MC1, MASK_31); in saa7146_init_one())
> 
> A restart of the drivers was not working, so I tried to 
> un-comment that piece of code. It worked, but I got three
> problems:
> 
> 1) Once, during a driver restart, the whole machine froze while
> loading the drivers.
> 
> 2) I automated that in my application, but I didn't put any sleep
> between the restart of the drivers and the re-opening of the
> frontend. That resulted in a kernel oops and my application ended
> up frozen. I solved that by putting a sleep in between. I guess
> there is some times after the start of the driver where it's not
> good to try open the frontend.

If you have a decoded/readable Oops message (i.e. from a 2.6
kernel, on 2.4 run "dmesg | ksymoops"), please post it here
so we can identifiy and fix this bug.

> 3) When I reload the drivers, the DVB cards (I have two) don't
> keep the same adapater id. But that's not a big deal...
> 
> Anyway, thanks for the trick. It does the job  :-)

Well, the question is now if the saa7146 gurus can come up
with a version of start_ts_capture() that does prevent
the problem from happening in the first place.

Johannes