[linux-dvb] Re: Problems with WinTV NOVA-CI

[w-thiel@gmx.net]

Hi Andrew,

On Wed, Dec 15, 2004 at 02:27:20AM +0000, Andrew de Quincey wrote:
> ...
> What I mean is - there aren't really many upper (driver) layers involved here: 
> basically tuning,  softdemux, and en50221.
> 
> Tuning we know always works OK.
> 
> People see this problem without en50221, so it can be ignored.
> 
> Softdemux works as follows: 
> * The demodulator delivers the entire transport stream to the saa7146.
> * The saa7146 sends the entire transport stream across the PCI bus.
> * The saa7146 driver gets an interrupt when data is ready, pulls the data from 
> the card, and sends it into the soft demuxer.
> * The soft demuxer extracts the PIDs the user wants and discards the rest.
> 
> The only thing that could go wrong is if the soft demux failed to call the 
> card specific start_feed()/stop_feed() implementations. These calls setup the 
> saa7146 to start sending data across the PCI bus, and stop sending it 
> respectively. I've just realised I'd assumed they worked fine as I've never 
> seen them fail - totally stupid mistake now I come to think of it.
> 
> However, this is a possibility - it would be good if you could check this, as 
> well as someone with the VDR/FF+budget problem. Basically set the 
> "budget_debug" parameter to 3 on the budget-core module. You should be able 
> to check if the calls to budget_start_feed()/budget_stop_feed() are happening 
> in dmesg.
> 
> Another thing to check would be to add some debugging printks into 
> budget-core.c/start_ts_capture() and budget-core.c/stop_ts_capture() to 
> ensure it is getting all the way through those functions - also that the 
> correct paths are being taken.
> 
Many thanks for your time and explanations.
I hope to have some time this weekend for more checks.

As the error appears both with ttpci-budget _and_ skystar2, the culprit
will - imho - be in dvb-core.

I just found
 http://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/

Perhaps chapter 7 will tell me what to look for when I find the time to
look at the sources.


Best regards, Wolfgang