[linux-dvb] Lockups with cx2388x cards

Steven Toth stoth at linuxtv.org
Thu Jan 10 18:41:15 CET 2008

Peter Martin wrote:
> I have a couple of Hauppauge cards (Nova-T using the cx2388x and a Nova 
> Plus, again using an cx2388x) in an industrial motherboard (an Axiomtek 
> ATX6022-14G) which is causing me some grief. After a short time I am 
> getting both cards locking up (no DMA) at the same time.

Does it happen with only a single card active in the system?

Have you tried the cards on other motherboards and do they operate 
successfully without error?

> In order to get these cards working at all in this configuration, I have 
> re-arranged the SRAM and increased the FIFO size in cx88-core.c to 
> 0x4800 bytes, and disabled all the other channels (video, audio etc), 
> which has cured the FIFO overflow errors I was getting ( general errors: 
> 0x00000100), but the cards still lock up. The cards can run from between 
> 5 seconds and 30 minutes before the lockup. I also get the lockups with 
> the stock code, so I am happy that my SRAM chganges have not broken 
> anything.

IIRC, the fifo is pretty small (resulting in potential short latency 
issues). This could be compounded with a busy DMA bus and short fifo's 
both competing for the same DMA queue resource. I suspect increasing the 
fifo really just masks the real DMA contension issue.

What else is happening DMA wise in your system?

- Steve

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