[media] v4l2: use new flag to enable core priority handling

Rather than guess which driver supports core priority handling, require drivers
that do to explicitly set the V4L2_FL_USE_FH_PRIO flag in video_device.

Updated the core prio handling accordingly and set the flag in the three
drivers that do.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/media/video/v4l2-fh.c b/drivers/media/video/v4l2-fh.c
index 543b3fe6784e..717f71e6370e 100644
--- a/drivers/media/video/v4l2-fh.c
+++ b/drivers/media/video/v4l2-fh.c
@@ -35,7 +35,6 @@ int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
         INIT_LIST_HEAD(&fh->list);
         set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
         fh->prio = V4L2_PRIORITY_UNSET;
-        BUG_ON(vdev->prio == NULL);
 
         /*
          * fh->events only needs to be initialized if the driver
@@ -54,7 +53,8 @@ void v4l2_fh_add(struct v4l2_fh *fh)
 {
         unsigned long flags;
 
-        v4l2_prio_open(fh->vdev->prio, &fh->prio);
+        if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
+                v4l2_prio_open(fh->vdev->prio, &fh->prio);
         spin_lock_irqsave(&fh->vdev->fh_lock, flags);
         list_add(&fh->list, &fh->vdev->fh_list);
         spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
@@ -82,7 +82,8 @@ void v4l2_fh_del(struct v4l2_fh *fh)
         spin_lock_irqsave(&fh->vdev->fh_lock, flags);
         list_del_init(&fh->list);
         spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
-        v4l2_prio_close(fh->vdev->prio, fh->prio);
+        if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
+                v4l2_prio_close(fh->vdev->prio, fh->prio);
 }
 EXPORT_SYMBOL_GPL(v4l2_fh_del);