diff options
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-core.c | 68 | ||||
| -rw-r--r-- | include/media/videobuf2-core.h | 15 |
2 files changed, 66 insertions, 17 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 14a360490be9..0d5b84f3b570 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1378,6 +1378,39 @@ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b) } EXPORT_SYMBOL_GPL(vb2_prepare_buf); +/** + * vb2_start_streaming() - Attempt to start streaming. + * @q: videobuf2 queue + * + * If there are not enough buffers, then retry_start_streaming is set to + * 1 and 0 is returned. The next time a buffer is queued and + * retry_start_streaming is 1, this function will be called again to + * retry starting the DMA engine. + */ +static int vb2_start_streaming(struct vb2_queue *q) +{ + int ret; + + /* Tell the driver to start streaming */ + ret = call_qop(q, start_streaming, q, atomic_read(&q->queued_count)); + + /* + * If there are not enough buffers queued to start streaming, then + * the start_streaming operation will return -ENOBUFS and you have to + * retry when the next buffer is queued. + */ + if (ret == -ENOBUFS) { + dprintk(1, "qbuf: not enough buffers, retry when more buffers are queued.\n"); + q->retry_start_streaming = 1; + return 0; + } + if (ret) + dprintk(1, "qbuf: driver refused to start streaming\n"); + else + q->retry_start_streaming = 0; + return ret; +} + static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) { int ret = vb2_queue_or_prepare_buf(q, b, "qbuf"); @@ -1426,6 +1459,12 @@ static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) /* Fill buffer information for the userspace */ __fill_v4l2_buffer(vb, b); + if (q->retry_start_streaming) { + ret = vb2_start_streaming(q); + if (ret) + return ret; + } + dprintk(1, "%s() of buffer %d succeeded\n", __func__, vb->v4l2_buf.index); return 0; } @@ -1575,7 +1614,8 @@ int vb2_wait_for_all_buffers(struct vb2_queue *q) return -EINVAL; } - wait_event(q->done_wq, !atomic_read(&q->queued_count)); + if (!q->retry_start_streaming) + wait_event(q->done_wq, !atomic_read(&q->queued_count)); return 0; } EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers); @@ -1689,6 +1729,11 @@ static void __vb2_queue_cancel(struct vb2_queue *q) { unsigned int i; + if (q->retry_start_streaming) { + q->retry_start_streaming = 0; + q->streaming = 0; + } + /* * Tell driver to stop all transactions and release all queued * buffers. @@ -1738,12 +1783,9 @@ static int vb2_internal_streamon(struct vb2_queue *q, enum v4l2_buf_type type) list_for_each_entry(vb, &q->queued_list, queued_entry) __enqueue_in_driver(vb); - /* - * Let driver notice that streaming state has been enabled. - */ - ret = call_qop(q, start_streaming, q, atomic_read(&q->queued_count)); + /* Tell driver to start streaming. */ + ret = vb2_start_streaming(q); if (ret) { - dprintk(1, "streamon: driver refused to start streaming\n"); __vb2_queue_cancel(q); return ret; } @@ -2313,15 +2355,15 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read) goto err_reqbufs; fileio->bufs[i].queued = 1; } - - /* - * Start streaming. - */ - ret = vb2_streamon(q, q->type); - if (ret) - goto err_reqbufs; } + /* + * Start streaming. + */ + ret = vb2_streamon(q, q->type); + if (ret) + goto err_reqbufs; + q->fileio = fileio; return ret; diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index ea766525a268..bef53ce555d2 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -252,10 +252,13 @@ struct vb2_buffer { * receive buffers with @buf_queue callback before * @start_streaming is called; the driver gets the number * of already queued buffers in count parameter; driver - * can return an error if hardware fails or not enough - * buffers has been queued, in such case all buffers that - * have been already given by the @buf_queue callback are - * invalidated. + * can return an error if hardware fails, in that case all + * buffers that have been already given by the @buf_queue + * callback are invalidated. + * If there were not enough queued buffers to start + * streaming, then this callback returns -ENOBUFS, and the + * vb2 core will retry calling @start_streaming when a new + * buffer is queued. * @stop_streaming: called when 'streaming' state must be disabled; driver * should stop any DMA transactions or wait until they * finish and give back all buffers it got from buf_queue() @@ -323,6 +326,9 @@ struct v4l2_fh; * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued * @alloc_ctx: memory type/allocator-specific contexts for each plane * @streaming: current streaming state + * @retry_start_streaming: start_streaming() was called, but there were not enough + * buffers queued. If set, then retry calling start_streaming when + * queuing a new buffer. * @fileio: file io emulator internal data, used only if emulator is active */ struct vb2_queue { @@ -355,6 +361,7 @@ struct vb2_queue { unsigned int plane_sizes[VIDEO_MAX_PLANES]; unsigned int streaming:1; + unsigned int retry_start_streaming:1; struct vb2_fileio_data *fileio; }; |