From: Pawel Osciak <posciak@xxxxxxxxxxxx> When using vb2 for video decoding, dequeued capture buffers may still be accessed by the hardware: this is the case when they are used as reference frames for decoding subsequent frames. When the buffer is imported with dma-buf, it needs to be mapped before access. Until now, it was mapped when queuing and unmapped when dequeuing, which doesn't work for access as a reference frames. One way to solve this would be to map the buffer again when it is needed as a reference, but the mapping/unmapping operations can seriously impact performance. As a result, map the buffer once (when it is first needed when queued) and keep it mapped until it is freed. Signed-off-by: Pawel Osciak <posciak@xxxxxxxxxxxx> Reviewed-on: https://chromium-review.googlesource.com/334103 Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx> [Paul: Updated for mainline and changed commit message] --- drivers/media/common/videobuf2/videobuf2-core.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index 70e8c3366f9c..ce9294a635cc 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -1196,6 +1196,9 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) * userspace knows sooner rather than later if the dma-buf map fails. */ for (plane = 0; plane < vb->num_planes; ++plane) { + if (vb->planes[plane].dbuf_mapped) + continue; + ret = call_memop(vb, map_dmabuf, vb->planes[plane].mem_priv); if (ret) { dprintk(1, "failed to map dmabuf for plane %d\n", @@ -1758,14 +1761,6 @@ static void __vb2_dqbuf(struct vb2_buffer *vb) vb->state = VB2_BUF_STATE_DEQUEUED; - /* unmap DMABUF buffer */ - if (q->memory == VB2_MEMORY_DMABUF) - for (i = 0; i < vb->num_planes; ++i) { - if (!vb->planes[i].dbuf_mapped) - continue; - call_void_memop(vb, unmap_dmabuf, vb->planes[i].mem_priv); - vb->planes[i].dbuf_mapped = 0; - } call_void_bufop(q, init_buffer, vb); } -- 2.20.1
