[linux-dvb] Re: DVB-T crashes Mandrake 9.1

[Bruno Prior <bruno@rpgd.uklinux.net>]

Hi Juri,

Juri Haberland wrote:
> Well, first, if you change your complete setup and start with drivers
> that are still in development you will certainly see problems.
I had this system running for 10 days without any problems in its current 
configuration before I tried to use DVB. It's not the change of setup that 
causes trouble, it's using the DVB drivers.

> Second, Linux is very well capable of sharing interrupts.
> My proof is the laptop I'm currently composing this email. Here is a
> snippet of 'cat /proc/interrupts':
>
>  11:    5536853          XT-PIC  usb-uhci, eth0, Texas Instruments
> PCI4451 PC card Cardbus Controller, Texas Instruments PCI4451 PC card
> Cardbus Controller (#2), nvidia
>
> So network, grafics card, usb and pcmcia share the same interrupt - no
> lockups at all.
That is what I have been told, and indeed on this system, the Radeon and 
SCSI card seem to be able to coexist happily, as do ide2 and ide3. I am 
suspicious that linux + Via + Athlon can cause IRQ trouble, but I have been 
told the problem is more likely DMA than IRQ. Either way, I am avoiding this 
combination like the plague in future. This Intel-based board is the first 
time I have seen more than 16 interrupts, which seems a bit strange. I don't 
know whether it is a good or bad thing. But as there are so many free 
interrupts, it seems strange that several cards still end up sharing.

> Third: you are hopefully aware that with that other glory OS you still
> have major trouble if your Hauppauge TV-card (not DVB) shares an
> interrupt with other cards, same is true for ISDN cards.
No, I'm not aware of that. All I know is that this card works adequately on 
Windows and barely at all on linux. Believe me, I hate Microsoft and 
Windows. I have set my home up as a Windows-free zone and am trying to move 
my company that way as well (servers and my laptop are now linux-only). I do 
not say this because I have an iota of affection for any other OS, just 
because it seems to me that linux is getting worse, not better, at handling 
the basics. My impression is that all my linux systems (and I run several 
between work and home) are less stable now than they were a couple of years ago.

> Bottom line:
> it all depends on the particular driver, not the OS.
Exactly. And the DVB driver seems to be extremely bad in this regard.

> I'd suggest to rip out the DVB card, make sure that no DVB drivers are
> loaded at system startup and run this system for a week stress testing
> it. If it still locks up your problem is elsewhere (most certainly
> hardware - ever run memtest86 on your system at least over night?).
As stated above, this machine ran fine for 10 days in this configuration 
(and even with the Nova-T installed). I have even had it running for 18 
hours now with the DVB modules inserted. It seems to be fine until the 
moment that I actually start trying to retrieve data from the devices. At 
that point it goes into an irq loop.

I am going to try Philip Armstrong's suggestion to boot with the noapic 
option first. If that doesn't work, I'll bow to the weight of opinion and 
see if I can find a slot where the DVB card is not sharing an interrupt. But 
I'll be saddened if that really is the solution. It seems contradictory to 
say that linux handles IRQ-sharing fine, and then to recommend changing a 
card's slot as the solution to the problem.

Thanks for your help, anyway.

Cheers,

Bruno Prior



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