Help: ISA DMA transfers limited to 8192 bytes?

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Hi all,

I'm currently working on a data acquisition driver for a proprietary hardware
ISA-attached to an embedded x86 system running kernel 2.2.15.

My driver works reasonably well with DMA transfers of up to 8192 bytes,
but fails miserably on larger blocks (kernel oops: dereferencing null pointer).

I don't find any more bugs in my own code, so I wonder whether there's a magical
kernel limit involved (8192 bytes equalling exactly two memory pages)?

I do get a proper DMA buffer allocated, I'm using __get_dma_pages() and yes,
with the correct "order" parameter. My driver oopses as soon as the first DMA
transfer starts.

Totally clueless, hoping for hints,
- Bernd

-- 
bernd kischnick email kisch@mindless.com tel +49-(0)511-18375
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