From 58d75f4b1ce26324b4d809b18f94819843a98731 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 20 Sep 2014 16:16:35 -0300 Subject: [PATCH] [media] vb2: fix VBI/poll regression The recent conversion of saa7134 to vb2 unconvered a poll() bug that broke the teletext applications alevt and mtt. These applications expect that calling poll() without having called VIDIOC_STREAMON will cause poll() to return POLLERR. That did not happen in vb2. This patch fixes that behavior. It also fixes what should happen when poll() is called when STREAMON is called but no buffers have been queued. In that case poll() will also return POLLERR, but only for capture queues since output queues will always return POLLOUT anyway in that situation. This brings the vb2 behavior in line with the old videobuf behavior. Signed-off-by: Hans Verkuil Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-core.c | 17 ++++++++++++++--- include/media/videobuf2-core.h | 4 ++++ 2 files changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index c2126d874549..25d3ae2188cb 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -971,6 +971,7 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) * to the userspace. */ req->count = allocated_buffers; + q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type); return 0; } @@ -1018,6 +1019,7 @@ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create memset(q->plane_sizes, 0, sizeof(q->plane_sizes)); memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx)); q->memory = create->memory; + q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type); } num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers); @@ -1821,6 +1823,7 @@ static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) */ list_add_tail(&vb->queued_entry, &q->queued_list); q->queued_count++; + q->waiting_for_buffers = false; vb->state = VB2_BUF_STATE_QUEUED; if (V4L2_TYPE_IS_OUTPUT(q->type)) { /* @@ -2287,6 +2290,7 @@ static int vb2_internal_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) * their normal dequeued state. */ __vb2_queue_cancel(q); + q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type); dprintk(3, "successful\n"); return 0; @@ -2605,10 +2609,17 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) } /* - * There is nothing to wait for if no buffer has been queued and the - * queue isn't streaming, or if the error flag is set. + * There is nothing to wait for if the queue isn't streaming, or if the + * error flag is set. */ - if ((list_empty(&q->queued_list) && !vb2_is_streaming(q)) || q->error) + if (!vb2_is_streaming(q) || q->error) + return res | POLLERR; + /* + * For compatibility with vb1: if QBUF hasn't been called yet, then + * return POLLERR as well. This only affects capture queues, output + * queues will always initialize waiting_for_buffers to false. + */ + if (q->waiting_for_buffers) return res | POLLERR; /* diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 80fa7253e483..2fefcf491aa8 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -380,6 +380,9 @@ struct v4l2_fh; * @start_streaming_called: start_streaming() was called successfully and we * started streaming. * @error: a fatal error occurred on the queue + * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for + * buffers. Only set for capture queues if qbuf has not yet been + * called since poll() needs to return POLLERR in that situation. * @fileio: file io emulator internal data, used only if emulator is active * @threadio: thread io internal data, used only if thread is active */ @@ -417,6 +420,7 @@ struct vb2_queue { unsigned int streaming:1; unsigned int start_streaming_called:1; unsigned int error:1; + unsigned int waiting_for_buffers:1; struct vb2_fileio_data *fileio; struct vb2_threadio_data *threadio;