[linux-dvb] Re: dvb-bt8xx and net device

[Holger Waechtler <holger@convergence.de>]

André Stein wrote:
>     First of all, I always set the MAC address manually because after 
> ifconfig -a dvb0_0 the mac address was always inited to 0.. Then the 
> driver actually never oops. It simply "fucks" up the whole system and I 
> don't know why..
>
> I made a similar approach as you. I tuned and brought the net device up 
> with dvbtune
>  # dvbtune -f 10773250 -p H -s 22000 -n 251 -i
> I get a long list of service available at the Astranet frequence and I 
> try to use the T-DSL proxy service (pid 251). Finally the net device is 
> successfully setup.
>  # ifconfig dvb0_0 10.0.1.1
> and the net device is running.. The mac is also set correctly as I 
> hardcoded it in the add_if net code.
>  # iptraf -d dvb0_0
> gets me lots of UDP packages but before I can actually start the proxy 
> service, the system hangs and nothing can't be done anymore. If you're 
> lucky you get data lost because the hd buffers weren't flushed..
>
> So after that I am pretty sure that this nasty bug isn't related with 
> setting the mac address. As I said before, I always set the mac before 
> using the net device and ifconfig -a dvb0_0 showed me that everything 
> went fine. It must be in some way related to the hardware as you're nova 
> s seems to work and Stefan reported the same problem as me with a 
> pinnacle card.
> As you're familiar with the dvb interface, is there a possibilty that a 
> package buffer is flooded with data that actually makes the kernel go 
> nuts?
well, I fear that the actual bug is in the bt8xx driver, somewhere in 
DMA setup and interrupt handling.

Is your system responding on SysRq-Keys after the lockup? Might it hang 
in a busy-loop somewhere, maybe in interrupt context? Try e.g. 
alt-sysrq-t or alt-sysrq-p to get an idea where the kernel is actually 
hanging. Remove the SA_INTERRUPT flag in request_irq() to enable other 
interrupts while processing bt878_irq().

In any case you might want to set up a serial console on a second box in 
order to save the logs.

Holger



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