[PATCH] media: videodev2: add V4L2_FMT_FLAG_NO_SOURCE_CHANGE

[Maxime Jourdan]

When a v4l2 driver exposes V4L2_EVENT_SOURCE_CHANGE, some (usually
OUTPUT) formats may not be able to trigger this event.

Add a enum_fmt format flag to tag those specific formats.

Signed-off-by: Maxime Jourdan <mjourdan@xxxxxxxxxxxx>
---
 Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 5 +++++
 include/uapi/linux/videodev2.h                   | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
index 019c513df217..e0040b36ac43 100644
--- a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
+++ b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
@@ -116,6 +116,11 @@ one until ``EINVAL`` is returned.
       - This format is not native to the device but emulated through
 	software (usually libv4l2), where possible try to use a native
 	format instead for better performance.
+    * - ``V4L2_FMT_FLAG_NO_SOURCE_CHANGE``
+      - 0x0004
+      - The event ``V4L2_EVENT_SOURCE_CHANGE`` is not supported
+	for this format.
+
 
 
 Return Value
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 3a65951ca51e..a28acee1cb52 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -723,8 +723,9 @@ struct v4l2_fmtdesc {
 	__u32		    reserved[4];
 };
 
-#define V4L2_FMT_FLAG_COMPRESSED 0x0001
-#define V4L2_FMT_FLAG_EMULATED   0x0002
+#define V4L2_FMT_FLAG_COMPRESSED	0x0001
+#define V4L2_FMT_FLAG_EMULATED		0x0002
+#define V4L2_FMT_FLAG_NO_SOURCE_CHANGE	0x0004
 
 	/* Frame Size and frame rate enumeration */
 /*
-- 
2.19.0