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SubjectRe: [PATCH v2 -resend#1 1/1] V4L: videobuf, don't use dma addr as physical
On 03/21/2011 11:43 PM, Mauro Carvalho Chehab wrote:
> As I got no return, and the patch looked sane, I've reviewed the comment myself,

Aha, I forgot to send it. Sorry.

It looks OK.

> Author: Jiri Slaby <jslaby@suse.cz>
> Date: Mon Feb 28 06:37:02 2011 -0300
>
> [media] V4L: videobuf, don't use dma addr as physical
>
> mem->dma_handle is a dma address obtained by dma_alloc_coherent which
> needn't be a physical address in presence of IOMMU, as
> a hardware IOMMU can (and most likely) will return a bus address where
> physical != bus address.
>
> So ensure we are remapping (remap_pfn_range) the right page in
> __videobuf_mmap_mapper by using virt_to_phys(mem->vaddr) and not
> mem->dma_handle.
>
> While at it, use PFN_DOWN instead of explicit shift.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
>
> diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c
> index c969111..19d3e4a 100644
> --- a/drivers/media/video/videobuf-dma-contig.c
> +++ b/drivers/media/video/videobuf-dma-contig.c
> @@ -300,7 +300,7 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
>
> vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> retval = remap_pfn_range(vma, vma->vm_start,
> - mem->dma_handle >> PAGE_SHIFT,
> + PFN_DOWN(virt_to_phys(mem->vaddr))
> size, vma->vm_page_prot);
> if (retval) {
> dev_err(q->dev, "mmap: remap failed with error %d. ", retval);

thanks,
--
js
suse labs


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