[v2] v4l2-compliance: call select before dequeuing event

Commit Message

Deborah Brouwer June 9, 2023, 1:52 a.m. UTC

When the streaming option is called with a stateful decoder,
testUserPtr() and testDmaBuf() will hang indefinitely when attempting to
dequeue a source change event. To prevent this call select() with a
timeout.

Signed-off-by: Deborah Brouwer <[e-mail]>
---
Changes since v1:
  Restore the file descriptor flags to remove non-blocking mode.

 utils/v4l2-compliance/v4l2-test-buffers.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Patch

diff --git a/utils/v4l2-compliance/v4l2-test-buffers.cpp b/utils/v4l2-compliance/v4l2-test-buffers.cpp
index a097a0ff..6d592c9b 100644
--- a/utils/v4l2-compliance/v4l2-test-buffers.cpp
+++ b/utils/v4l2-compliance/v4l2-test-buffers.cpp
@@ -1746,9 +1746,19 @@  int testUserPtr(struct node *node, struct node *node_m2m_cap, unsigned frame_cou
 
 		if (node->is_m2m) {
 			if (node->codec_mask & STATEFUL_DECODER) {
+				int fd_flags = fcntl(node->g_fd(), F_GETFL);
+				struct timeval tv = { 1, 0 };
+				fd_set efds;
 				v4l2_event ev;
 
+				fcntl(node->g_fd(), F_SETFL, fd_flags | O_NONBLOCK);
+				FD_ZERO(&efds);
+				FD_SET(node->g_fd(), &efds);
+				ret = select(node->g_fd() + 1, nullptr, nullptr, &efds, &tv);
+				fail_on_test_val(ret < 0, ret);
+				fail_on_test(ret == 0);
 				fail_on_test(node->dqevent(ev));
+				fcntl(node->g_fd(), F_SETFL, fd_flags);
 				fail_on_test(ev.type != V4L2_EVENT_SOURCE_CHANGE);
 				fail_on_test(!(ev.u.src_change.changes & V4L2_EVENT_SRC_CH_RESOLUTION));
 			}
@@ -1949,9 +1959,19 @@  int testDmaBuf(struct node *expbuf_node, struct node *node, struct node *node_m2
 
 		if (node->is_m2m) {
 			if (node->codec_mask & STATEFUL_DECODER) {
+				int fd_flags = fcntl(node->g_fd(), F_GETFL);
+				struct timeval tv = { 1, 0 };
+				fd_set efds;
 				v4l2_event ev;
 
+				fcntl(node->g_fd(), F_SETFL, fd_flags | O_NONBLOCK);
+				FD_ZERO(&efds);
+				FD_SET(node->g_fd(), &efds);
+				ret = select(node->g_fd() + 1, nullptr, nullptr, &efds, &tv);
+				fail_on_test_val(ret < 0, ret);
+				fail_on_test(ret == 0);
 				fail_on_test(node->dqevent(ev));
+				fcntl(node->g_fd(), F_SETFL, fd_flags);
 				fail_on_test(ev.type != V4L2_EVENT_SOURCE_CHANGE);
 				fail_on_test(!(ev.u.src_change.changes & V4L2_EVENT_SRC_CH_RESOLUTION));
 			}