| Message ID | 20200609060417.8066-1-sergey.senozhatsky@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | videobuf2: always re-init queue memory consistency attribute | expand |
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index 7e081716b8da..37d0186ba330 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -704,12 +704,11 @@ EXPORT_SYMBOL(vb2_verify_memory_type); static void set_queue_consistency(struct vb2_queue *q, bool consistent_mem) { + q->dma_attrs &= ~DMA_ATTR_NON_CONSISTENT; + if (!vb2_queue_allows_cache_hints(q)) return; - - if (consistent_mem) - q->dma_attrs &= ~DMA_ATTR_NON_CONSISTENT; - else + if (!consistent_mem) q->dma_attrs |= DMA_ATTR_NON_CONSISTENT; }
We need a combination of two factors in order to permit modification of queue's memory consistency attribute in set_queue_consistency(): (1) queue should allow user-space cache hints (2) queue should be used for MMAP-ed I/O Therefore the code in videobuf2 core looks as follows: q->memory = req->memory; set_queue_consistency(q, consistent); This works when we do something like this (suppose that queue allows cache hints) reqbufs.memory = V4L2_MEMORY_DMABUF; reqbufs.flags = 0; doioctl(node, VIDIOC_REQBUFS, &reqbufs); reqbufs.memory = V4L2_MEMORY_MMAP; reqbufs.flags = V4L2_FLAG_MEMORY_NON_CONSISTENT; doioctl(node, VIDIOC_REQBUFS, &reqbufs); However, this doesn't work the other way around reqbufs.memory = V4L2_MEMORY_MMAP; reqbufs.flags = V4L2_FLAG_MEMORY_NON_CONSISTENT; doioctl(node, VIDIOC_REQBUFS, &reqbufs); reqbufs.memory = V4L2_MEMORY_DMABUF; reqbufs.flags = 0; doioctl(node, VIDIOC_REQBUFS, &reqbufs); because __vb2_queue_free() doesn't clear queue's ->dma_attrs once its don't freeing queue buffers, and by the time we call set_queue_consistency() the queue is DMABUF so (2) is false and we never clear the stale consistency attribute. Re-implement set_queue_consistency() - it must always clear queue's non-consistency attr and set it only if (1) and (2). Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> --- drivers/media/common/videobuf2/videobuf2-core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)