On 12/10/2021 17:16, Hans Verkuil wrote:
On 05/10/2021 10:57, Tomi Valkeinen wrote:
All suitable subdev ops are now passed either the TRY or the ACTIVE
state by the v4l2 core. However, other subdev drivers can still call the
ops passing NULL as the state, implying the active case.
For all current upstream drivers this doesn't matter, as they do not
expect to get a valid state for ACTIVE case. But future drivers which
support multiplexed streaming and routing will depend on getting a state
for both active and try cases.
For new drivers we can mandate that the pipelines where the drivers are
used need to pass the state properly, or preferably, not call such
subdev ops at all.
However, if an existing subdev driver is changed to support multiplexed
streams, the driver has to consider cases where its ops will be called
with NULL state. The problem can easily be solved by using the
v4l2_subdev_validate_and_lock_state() helper, introduced here.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
include/media/v4l2-subdev.h | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a6e8f531a396..b75eeaee492b 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1313,4 +1313,37 @@ void v4l2_subdev_lock_state(struct v4l2_subdev_state *state);
*/
void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state);
+/**
+ * v4l2_subdev_validate_and_lock_state() - Gets locked TRY or ACTIVE subdev
I think this name is confusing since it isn't validating anything.
I'd call it v4l2_subdev_lock_and_return_state().
Yes, I really didn't like the name either.
v4l2_subdev_lock_and_return_state() isn't quite perfect either, as it
sounds like it just locks and returns the given state. But I think it's
better than the current name, so I'll change.
Tomi
