>
> Now, I see that the requested videobuffers are correctly allocated via 'vb2_dma_contig_alloc'
> call (see [3] for reference). But the MMAP call fails in 'vb2_dma_contig_alloc' function
> in mm/nommu.c (see [4] for reference) when it tries to make the following check:
>
> if (addr != (pfn << PAGE_SHIFT))
> return -EINVAL;
>
> I address Scott also, as I see that he has worked on the Blackfin v4l2 capture driver using
> DMA contiguous method and may have seen this issue (on a NOMMU system) with a v4l2 application
> performing a MMAP operation.
>
> Any comments on what I could be doing wrong here?
>
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t prot)
{
if ((addr & PAGE_MASK) != (pfn << PAGE_SHIFT))
return -EINVAL;
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
return 0;
}
This patch seems not in current kernel. Hope it can resolve your problem.
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