[linux-dvb] Re: dvb stream stops after 5 secs...

[Holger Waechtler <holger@convergence.de>]

Tomi Ollila wrote:
> Hi
> 
> I have nova-t, and I am now testing DVB driver and dvbtools/dvbstream 
> downloaded yesterday.
> 
> (as a side note, in my first test I got my computer crashed, with 
>  blinking Caps Lock and Scroll Lock lights. I played al little with
>  insmodding, tried to do that manuall first, but then reverted to the
>  `make insmod'. Now after trying ./dvbstream ... | mplayer ... The
>  machine crashed. The same thing has happened with old driver last
>  time in July...
>  If anyone know how I could debug such thing, I could try to push
>  the system and try to recreate a situation when it crashes -- after
>  that first time it has not crashed, but I've been gentle with it).

Connect a second computer to the serial port, configure 'serial console 
support' in your kernel and tell him to dump the kernel messages to this 
console (console=... kernel parameter). Then you can log and analyze 
your oopses on the second machine even if the first one is hard-locking.


> First, I "installed" modules to the running kernel using `make insmod'
> (after makedev.napi of course), and when using DVB with
> ./dvbstream and mplayer the system worked quite well, I could watch
> digital television (though I once got jerky pictures with broken
> macroblocks all the time -- that went away after rerun. I'd quess
> the jerkiness becan when my machine started updatdb cycle, but it
> did not go away after updatedb was ready -- but that is just wild
> quess).
> 
> Well, after that I decided to do `make install' in DVB/driver -directory
> and then appended modules.conf to /etc/modules.conf (on Red Hat 8.0 machine)
> and then rebooted
> 
> After reboot I tried running dvbstream ... | mplayer ... It did not work.
> The I tried the same as root. Did not work either. Ok. Let's try to
> add `alias char-major-250 dvb-ttpci', analogy to some other stuff;
> now I have at the end of /etc/modules.conf:
> 
> probeall /dev/dvb dvb-ttpci
> alias char-major-250 dvb-ttpci
> alias /dev/dvb/* /dev/dvb
> below dvb-ttpci alps_bsru6 alps_bsrv2 grundig_29504-401
> add below dvb-ttpci grundig_29504-491 ves1820 alps_tdmb7 alps_tdlb7
> 
> Now. dvbstream -f $FREQ $VPID $APID -ps -o | \
>      mplayer -quiet -hardframedrop $DXROPTS -cache 2048 -
> 
> worked ... but only something like 5 seconds, then video stalled. rerun. 
> same happened. Hmm, maybe that option in insmod target: 
> dvb_shutdown_timeout=0 affects it.
> -- or then maybe not. anyway. Now I run `top' on another window.
> Now I saw kdvb-fe... visiting the TOP listing. after a while I could
> not find it in top or ps outputs.

it's the kdvb-fe thread. Either set dvb_shutdown_timeout=0 or patch 
dvbstream so that it keeps the frontend file descriptor open as long it 
is using the DVB hardware. This is the right way (tm).


> So, does the missing option dvb_shutdown_timeout affect like i described,
> or is there still something missing in /etc/modules.conf? Or does
> dvbstream open the device wrong way so that it closes itself...

no DVB application should ever close a device when it still needs it 
working.

Holger



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