How to work out the cause of a DMA Bus Error (QCI PXA320)?

[Guennadi Liakhovetski]

On Thu, 27 Aug 2009, Judith Baumgarten wrote:

> Hi,
> 
> I'm still working on the pxa_camera driver for PXA320.

Is this a new driver or an extension to pxa270?

> At the moment I can
> capture some frames (RAW mode), but then I get a DMA Bus Error. Has anyone an
> idea how to deal with that error or work out the specific cause?
> The manual says, that if an error occures the channel is stopped until it's
> reprogrammed and the corresponding RUN bit is set, but there are no RUN bits
> in QCI DMA. So I don't see a chance to start it again...

I think we also had some DMA issues on pxa270, but we fixed them latest 
with these patches:

"V4L/DVB (11322): pxa_camera: Fix overrun condition on last buffer"
"V4L/DVB (11321): pxa_camera: Redesign DMA handling"

if you're writing a new driver, have a look t pxa270 and at those patches 
specifically.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/