[PATCH v4 7/8] utils/common: Set V4L2_SUBDEV_CLIENT_CAP_STREAMS for subdevs

[Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>]

Do two things:

- Inform the kernel that we support streams with a call to
  VIDIOC_SUBDEV_S_CLIENT_CAP

- Use the returns from VIDIOC_SUBDEV_S_CLIENT_CAP and
  VIDIOC_SUBDEV_QUERYCAP to decide if streams are supported, and
  return that via has_streams_support() method.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
 utils/common/cv4l-helpers.h |  1 +
 utils/common/v4l-helpers.h  | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/utils/common/cv4l-helpers.h b/utils/common/cv4l-helpers.h
index 3cee372b..502df6ac 100644
--- a/utils/common/cv4l-helpers.h
+++ b/utils/common/cv4l-helpers.h
@@ -82,6 +82,7 @@ public:
 	bool has_rw() const { return v4l_has_rw(this); }
 	bool has_streaming() const { return v4l_has_streaming(this); }
 	bool has_ext_pix_format() const { return v4l_has_ext_pix_format(this); }
+	bool has_streams_support() const { return subdev_supports_streams; }
 
 	int querycap(v4l2_capability &cap, bool force = false)
 	{
diff --git a/utils/common/v4l-helpers.h b/utils/common/v4l-helpers.h
index c09cd987..2dd7f061 100644
--- a/utils/common/v4l-helpers.h
+++ b/utils/common/v4l-helpers.h
@@ -39,6 +39,7 @@ struct v4l_fd {
 	bool have_selection;
 	bool is_subdev;
 	bool is_media;
+	bool subdev_supports_streams;
 
 	int (*open)(struct v4l_fd *f, const char *file, int oflag, ...);
 	int (*close)(struct v4l_fd *f);
@@ -507,6 +508,12 @@ static inline int v4l_open(struct v4l_fd *f, const char *devname, bool non_block
 
 static inline int v4l_subdev_s_fd(struct v4l_fd *f, int fd, const char *devname)
 {
+	struct v4l2_subdev_client_capability clientcap = {};
+	struct v4l2_subdev_capability subdevcap = {};
+	bool subdev_streams;
+	bool client_streams;
+	int ret;
+
 	if (f->fd >= 0)
 		f->close(f);
 
@@ -528,6 +535,16 @@ static inline int v4l_subdev_s_fd(struct v4l_fd *f, int fd, const char *devname)
 	f->have_next_ctrl = false;
 	f->have_selection = false;
 
+	ret = ioctl(f->fd, VIDIOC_SUBDEV_QUERYCAP, &subdevcap);
+	subdev_streams = !ret && (subdevcap.capabilities & V4L2_SUBDEV_CAP_STREAMS);
+
+	clientcap.capabilities = V4L2_SUBDEV_CLIENT_CAP_STREAMS;
+
+	ret = ioctl(f->fd, VIDIOC_SUBDEV_S_CLIENT_CAP, &clientcap);
+	client_streams = !ret && (clientcap.capabilities & V4L2_SUBDEV_CLIENT_CAP_STREAMS);
+
+	f->subdev_supports_streams = subdev_streams && client_streams;
+
 	return f->fd;
 }
 
-- 
2.34.1