Laurent -
On 03/18/15 09:59, Laurent Pinchart wrote:
Hi Tim,
The names might be a bit misleading, vb2-dma-contig requires contiguous memory
in the device memory space, not in physical memory. The IOMMU, managed through
dma_map_sg_attrs, should have mapped the userptr buffer contiguously in the
ISP DMA address space. If it hasn't, that's what need to be investigated.
I see now that it's the sg_dma_address(...) call that it's using and I
was assuming that was the physical memory address for the memory backing
up the buffer.
So the vb2_dc_get_contiguous_size(...) should be against the view of
memory that the IOMMU presents to the OMAP3 ISP? That is, the DMA
addresses that the OMAP3 ISP can see? I was assuming it was checking
the physical memory layout to it without looking too closely to the
code. Armed with that knowledge, I'll dig a little deeper to see if I
can figure out what happened here.
- Tim
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