mem->dma_handle is a dma address obtained by dma_alloc_coherent which needn't be a physical address 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 to obtain a frame number. This was discovered by a random review of the code when looking for something completely different. I'm not aware of any bug reports for this. However it is a bug because many v4l drivers use this layer and have no idea whether IOMMU is in the system and running or not. Signed-off-by: Jiri Slaby <[email protected]> Cc: Mauro Carvalho Chehab <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> --- This is a version with updated changelog. drivers/media/video/videobuf-dma-contig.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) 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); -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
