media: subdev: Fix use of sd->enabled_streams in call_s_stream()

call_s_stream() uses sd->enabled_streams to track whether streaming has
already been enabled. However,
v4l2_subdev_enable/disable_streams_fallback(), which was the original
user of this field, already uses it, and
v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream().

This leads to a conflict as both functions set the field. Afaics, both
functions set the field to the same value, so it won't cause a runtime
bug, but it's still wrong and if we, e.g., change how
v4l2_subdev_enable/disable_streams_fallback() operates we might easily
cause bugs.

Fix this by adding a new field, 's_stream_enabled', for
call_s_stream().

Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 09b4122d9ab7c22175c3ba0033e3b2d5f6761596..8675ad0688af68117de8687837e1c19bcea4178b 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -451,12 +451,8 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
         * The .s_stream() operation must never be called to start or stop an
         * already started or stopped subdev. Catch offenders but don't return
         * an error yet to avoid regressions.
-        *
-        * As .s_stream() is mutually exclusive with the .enable_streams() and
-        * .disable_streams() operation, we can use the enabled_streams field
-        * to store the subdev streaming state.
         */
-       if (WARN_ON(!!sd->enabled_streams == !!enable))
+       if (WARN_ON(sd->s_stream_enabled == !!enable))
                return 0;
 
        ret = sd->ops->video->s_stream(sd, enable);
@@ -467,7 +463,7 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
        }
 
        if (!ret) {
-               sd->enabled_streams = enable ? BIT(0) : 0;
+               sd->s_stream_enabled = enable;
 
                if (enable)
                        v4l2_subdev_enable_privacy_led(sd);

diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index e30c463d90e51a74a2816189950af8d6684734d0..d3f15882927b414aa81b928a69e2f5bd7353beb5 100644 (file)
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1045,6 +1045,8 @@ struct v4l2_subdev_platform_data {
  *                  v4l2_subdev_enable_streams() and
  *                  v4l2_subdev_disable_streams() helper functions for fallback
  *                  cases.
+ * @s_stream_enabled: Tracks whether streaming has been enabled with s_stream.
+ *                    This is only for call_s_stream() internal use.
  *
  * Each instance of a subdev driver should create this struct, either
  * stand-alone or embedded in a larger struct.
@@ -1093,6 +1095,7 @@ struct v4l2_subdev {
         */
        struct v4l2_subdev_state *active_state;
        u64 enabled_streams;
+       bool s_stream_enabled;
 };