Since the stream API is still experimental it is currently locked away
behind the internal, default disabled, v4l2_subdev_enable_streams_api flag.
Advertising V4L2_SUBDEV_CAP_STREAMS when the streams API is disabled
confuses userspace. E.g. it causes the following libcamera error:
ERROR SimplePipeline simple.cpp:1497 Failed to reset routes for
/dev/v4l-subdev1: Inappropriate ioctl for device
Don't report V4L2_SUBDEV_CAP_STREAMS when the streams API is disabled
to avoid problems like this.
Reported-by: Dennis Bonke <admin@xxxxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
-Clearing the V4L2_SUBDEV_FL_STREAMS flag from sd.flags might seem
appealing as an alternative fix. But this causes various v4l2-core bits
to enter different code paths which confuses drivers which set
V4L2_SUBDEV_FL_STREAMS, so this is a bad idea.
-No Closes: for the Reported-by since this was reported by private email
---
drivers/media/v4l2-core/v4l2-subdev.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index b92348ad61f6..31752c06d1f0 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -502,6 +502,13 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
V4L2_SUBDEV_CLIENT_CAP_STREAMS;
int rval;
+ /*
+ * If the streams API is not enabled, remove V4L2_SUBDEV_CAP_STREAMS.
+ * Remove this when the API is no longer experimental.
+ */
+ if (!v4l2_subdev_enable_streams_api)
+ streams_subdev = false;
+
switch (cmd) {
case VIDIOC_SUBDEV_QUERYCAP: {
struct v4l2_subdev_capability *cap = arg;
--
2.41.0
