v4l2: pool: Flush events on capture queue

Unfortunately streamoff does not flush the events, and this can cause all
sort of issues. Flush events on capture queue. We also return
GST_V4L2_FLOW_RESOLUTION_CHANGE in case a resolution change was seen.
This allow skipping streamon(capture) on flush, which could lead to a
configuration miss-match, or failure if the buffers aren't of the right
size.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4525>
This commit is contained in:
Nicolas Dufresne 2023-04-26 15:58:23 -04:00 committed by GStreamer Marge Bot
parent c93545f5b7
commit a9d5e44094
3 changed files with 60 additions and 8 deletions

View file

@ -2215,22 +2215,69 @@ gst_v4l2_buffer_pool_copy_at_threshold (GstV4l2BufferPool * pool, gboolean copy)
GST_OBJECT_UNLOCK (pool);
}
gboolean
static GstFlowReturn
gst_v4l2_buffer_pool_flush_events (GstV4l2Object * v4l2object)
{
GstFlowReturn ret = GST_FLOW_OK;
gboolean event_found;
/* FIXME simplify this when we drop legacy support for driver without poll()
* support. When we do, we can switch the video_fd to non blocking, and just
* pop the events directly. */
do {
struct v4l2_event event = { 0, };
gint poll_ret;
event_found = FALSE;
gst_poll_set_flushing (v4l2object->poll, FALSE);
do {
/* GstPoll don't have 0ns timeout, but 1 will do */
poll_ret = gst_poll_wait (v4l2object->poll, 1);
} while (poll_ret == EAGAIN || poll_ret == EINTR);
if (gst_poll_fd_has_pri (v4l2object->poll, &v4l2object->pollfd)) {
if (!gst_v4l2_dequeue_event (v4l2object, &event))
return GST_FLOW_ERROR;
event_found = TRUE;
if (event.type == V4L2_EVENT_SOURCE_CHANGE &&
(event.u.src_change.changes & V4L2_EVENT_SRC_CH_RESOLUTION)) {
GST_DEBUG_OBJECT (v4l2object->dbg_obj,
"Can't streamon capture as the resolution have changed.");
ret = GST_V4L2_FLOW_RESOLUTION_CHANGE;
}
}
} while (event_found);
return ret;
}
GstFlowReturn
gst_v4l2_buffer_pool_flush (GstV4l2Object * v4l2object)
{
GstBufferPool *bpool = gst_v4l2_object_get_buffer_pool (v4l2object);
GstV4l2BufferPool *pool;
gboolean ret = TRUE;
GstFlowReturn ret = GST_FLOW_OK;
if (!bpool)
return FALSE;
return GST_FLOW_ERROR;
pool = GST_V4L2_BUFFER_POOL (bpool);
gst_v4l2_buffer_pool_streamoff (pool);
if (!V4L2_TYPE_IS_OUTPUT (pool->obj->type))
ret = gst_v4l2_buffer_pool_streamon (pool);
if (!V4L2_TYPE_IS_OUTPUT (pool->obj->type)) {
ret = gst_v4l2_buffer_pool_flush_events (v4l2object);
/* If the format haven't change, avoid reallocation to go back to
* streaming */
if (ret == GST_FLOW_OK)
ret = gst_v4l2_buffer_pool_streamon (pool);
}
gst_object_unref (bpool);
return ret;

View file

@ -115,7 +115,7 @@ void gst_v4l2_buffer_pool_set_other_pool (GstV4l2BufferPool * poo
void gst_v4l2_buffer_pool_copy_at_threshold (GstV4l2BufferPool * pool,
gboolean copy);
gboolean gst_v4l2_buffer_pool_flush (GstV4l2Object * v4l2object);
GstFlowReturn gst_v4l2_buffer_pool_flush (GstV4l2Object * v4l2object);
gboolean gst_v4l2_buffer_pool_orphan (GstV4l2Object * v4l2object);

View file

@ -348,8 +348,12 @@ gst_v4l2_video_dec_flush (GstVideoDecoder * decoder)
/* gst_v4l2_buffer_pool_flush() calls streamon the capture pool and must be
* called after gst_v4l2_object_unlock_stop() stopped flushing the buffer
* pool. */
gst_v4l2_buffer_pool_flush (self->v4l2capture);
* pool. If the resolution has changed before we stopped the driver we must
* reallocate the capture pool. We simply discard the pool, and let the
* capture thread handle re-allocation.*/
if (gst_v4l2_buffer_pool_flush (self->v4l2capture) ==
GST_V4L2_FLOW_RESOLUTION_CHANGE || self->draining)
gst_v4l2_object_stop (self->v4l2capture);
return TRUE;
}
@ -888,6 +892,7 @@ beach:
GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
return;
}
GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
}