Re: DMA Transfer problem

From: James Courtier-Dutton
Date: Tue Jan 24 2006 - 07:58:05 EST


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

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