[linux-dvb] Re: Pinnacle PCTV

[peter.hettkamp@t-online.de (Peter Hettkamp)]

Michael,

I suppose you are right. I know there is a condition in my current
driver which causes the kernel to lock up; this is mostly triggered
when the frontend loses lock.
I am afraid I don't see why DvbDmxSWFilterPackets() needs to be called
with interrupts disabled, can you please enlighten me?

I'll just test if your patch woks with my system as well, then have it
included into the experimental-pinnacle branch.

Thank you very much,
Peter

P.S.: I have no idea why SMP kernels lock up, but I am pretty positive
I made some mistake with the spin_locks. Obviously, I do not quite
understand spin_locking :-(

On Sun, Aug 04, 2002 at 05:07:55PM +0200, michael.smutka@ycn.com wrote:
> 
> Dear Peter
> 
> For short: After a bit of fiddling it works.
> 
> I think I have found a race causing a deadlock even on UP kernels:
> 
> mike@lithium:/home/mike/play/DVB/DVB > cvs -d :pserver:anonymous@linuxtv.org:/cvs/linuxtv diff driver/dvb_demux.c
> Index: driver/dvb_demux.c
> ===================================================================
> RCS file: /cvs/linuxtv/DVB/driver/dvb_demux.c,v
> retrieving revision 1.29
> diff -r1.29 dvb_demux.c
> 412c412
> <       spin_lock(&dvbdmx->lock);
> ---
> >       spin_lock_irq(&dvbdmx->lock);
> 421c421
> <       spin_unlock(&dvbdmx->lock);
> ---
> >       spin_unlock_irq(&dvbdmx->lock);
> 
> In the original (non experimantal-pinnacle) version
> DvbDmxSWFilterPackets() is only called from interrupt context,
> therefore a lock without disabling the interrupts is OK. In the
> pinnacle version this is called by the tasklet, so disabling
> interrupts is necessary.
> 
> Unfortunately above fix does not help on SMP kernels, even with only
> one CPU :-(
> 
> Cheers
> Michael

-- 
"Only wimps use tape backup: _real_ men just upload their important stuff
on ftp, and let the rest of the world mirror it ;)"
(Linus Torvalds, about his failing hard drive on linux.cs.helsinki.fi)


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