Re: DMA Transfer problem

[James Courtier-Dutton <James@superbug.co.uk>]

Harish K Harshan wrote:
> Hello,
>
>   Im having problems with DMA transfer on Linux, for an ADC card. The 
> card is AxiomTek AX5621H, and can use DMA channels 1 and 3. I tried 
> both the channels, but the DMA transfers are irregular (i.e.) at 
> different speeds (which of course is not acceptable, since that 
> application is time critical). The device driver (which I wrote) seems 
> to work fine for all the other systems I tried it on. But this problem 
> occurs only on one particular model of computer (Chino-Laxsons 
> Pentium-4 boards). I tried another system with the same configuration, 
> but the same resulted. After some time of execution, I get the kernel 
> panic screen, which says the CPU context is corrupt. Please help me 
> with this problem, as I need to get this driver working somehow on the 
> P4 systems. I tried the Redhat-9 kernel (2.4.20-8) and the debian 
> kernel too (2.2.20).... gave the same results.
>
Could an ADC card be treated as a ALSA sound card PCM device.
That card seems to have features very similar to a sound card.
Sample rate.
Variable gain.
Multi-channels.
ADC
DMA

I only suggest this, because it could result in a driver that is much 
easier to implement as ALSA supplies a lot of generalised support code 
at the kernel level.

James