Hi Helen,
On Mon, Apr 03, 2017 at 12:11:54PM -0300, Helen Koike wrote:
> Hi,
>
> On 2017-03-31 06:57 AM, Mauro Carvalho Chehab wrote:
> >Em Fri, 31 Mar 2017 10:29:04 +0200
> >Hans Verkuil <hverkuil@xxxxxxxxx> escreveu:
> >
> >>On 30/03/17 18:02, Helen Koike wrote:
> >>>Add V4L2_INPUT_TYPE_DEFAULT and helpers functions for input ioctls to be
> >>>used when no inputs are available in the device
> >>>
> >>>Signed-off-by: Helen Koike <helen.koike@xxxxxxxxxxxxx>
> >>>---
> >>> drivers/media/v4l2-core/v4l2-ioctl.c | 27 +++++++++++++++++++++++++++
> >>> include/media/v4l2-ioctl.h | 26 ++++++++++++++++++++++++++
> >>> include/uapi/linux/videodev2.h | 1 +
> >>> 3 files changed, 54 insertions(+)
> >>>
> >>>diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> >>>index 0c3f238..ccaf04b 100644
> >>>--- a/drivers/media/v4l2-core/v4l2-ioctl.c
> >>>+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> >>>@@ -2573,6 +2573,33 @@ struct mutex *v4l2_ioctl_get_lock(struct video_device *vdev, unsigned cmd)
> >>> return vdev->lock;
> >>> }
> >>>
> >>>+int v4l2_ioctl_enum_input_default(struct file *file, void *priv,
> >>>+ struct v4l2_input *i)
> >>>+{
> >>>+ if (i->index > 0)
> >>>+ return -EINVAL;
> >>>+
> >>>+ memset(i, 0, sizeof(*i));
> >>>+ i->type = V4L2_INPUT_TYPE_DEFAULT;
> >>>+ strlcpy(i->name, "Default", sizeof(i->name));
> >>>+
> >>>+ return 0;
> >>>+}
> >>>+EXPORT_SYMBOL(v4l2_ioctl_enum_input_default);
> >>>+
> >>>+int v4l2_ioctl_g_input_default(struct file *file, void *priv, unsigned int *i)
> >>>+{
> >>>+ *i = 0;
> >>>+ return 0;
> >>>+}
> >>>+EXPORT_SYMBOL(v4l2_ioctl_g_input_default);
> >>>+
> >>>+int v4l2_ioctl_s_input_default(struct file *file, void *priv, unsigned int i)
> >>>+{
> >>>+ return i ? -EINVAL : 0;
> >>>+}
> >>>+EXPORT_SYMBOL(v4l2_ioctl_s_input_default);
> >>>+
> >>> /* Common ioctl debug function. This function can be used by
> >>> external ioctl messages as well as internal V4L ioctl */
> >>> void v4l_printk_ioctl(const char *prefix, unsigned int cmd)
> >>>diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> >>>index 6cd94e5..accc470 100644
> >>>--- a/include/media/v4l2-ioctl.h
> >>>+++ b/include/media/v4l2-ioctl.h
> >>>@@ -652,6 +652,32 @@ struct video_device;
> >>> */
> >>> struct mutex *v4l2_ioctl_get_lock(struct video_device *vdev, unsigned int cmd);
> >>>
> >>>+
> >>>+/**
> >>>+ * v4l2_ioctl_enum_input_default - v4l2 ioctl helper for VIDIOC_ENUM_INPUT ioctl
> >>>+ *
> >>>+ * Plug this function in vidioc_enum_input field of the struct v4l2_ioctl_ops to
> >>>+ * enumerate a single input as V4L2_INPUT_TYPE_DEFAULT
> >>>+ */
> >>>+int v4l2_ioctl_enum_input_default(struct file *file, void *priv,
> >>>+ struct v4l2_input *i);
> >>>+
> >>>+/**
> >>>+ * v4l2_ioctl_g_input_default - v4l2 ioctl helper for VIDIOC_G_INPUT ioctl
> >>>+ *
> >>>+ * Plug this function in vidioc_g_input field of the struct v4l2_ioctl_ops
> >>>+ * when using v4l2_ioctl_enum_input_default
> >>>+ */
> >>>+int v4l2_ioctl_g_input_default(struct file *file, void *priv, unsigned int *i);
> >>>+
> >>>+/**
> >>>+ * v4l2_ioctl_s_input_default - v4l2 ioctl helper for VIDIOC_S_INPUT ioctl
> >>>+ *
> >>>+ * Plug this function in vidioc_s_input field of the struct v4l2_ioctl_ops
> >>>+ * when using v4l2_ioctl_enum_input_default
> >>>+ */
> >>>+int v4l2_ioctl_s_input_default(struct file *file, void *priv, unsigned int i);
> >>>+
> >>> /* names for fancy debug output */
> >>> extern const char *v4l2_field_names[];
> >>> extern const char *v4l2_type_names[];
> >>>diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> >>>index 316be62..c10bbde 100644
> >>>--- a/include/uapi/linux/videodev2.h
> >>>+++ b/include/uapi/linux/videodev2.h
> >>>@@ -1477,6 +1477,7 @@ struct v4l2_input {
> >>> };
> >>>
> >>> /* Values for the 'type' field */
> >>>+#define V4L2_INPUT_TYPE_DEFAULT 0
> >>
> >>I don't think we should add a new type here.
> >
> >I second that. Just replied the same thing on a comment from Sakari to
> >patch 2/2.
> >
> >>The whole point of this exercise is to
> >>allow existing apps to work, and existing apps expect a TYPE_CAMERA.
> >>
> >>BTW, don't read to much in the term 'CAMERA': it's really a catch all for any video
> >>stream, whether it is from a sensor, composite input, HDMI, etc.
> >>
> >>The description for V4L2_INPUT_TYPE_CAMERA in the spec is hopelessly out of date :-(
> >
> >Yeah, we always used "CAMERA" to mean NOT_TUNER.
> >
> >>Rather than creating a new type I would add a new V4L2_IN_CAP_MC capability that
> >>indicates that this input is controlled via the media controller. That makes much
> >>more sense and it wouldn't potentially break applications.
> >>
> >>Exactly the same can be done for outputs as well: add V4L2_OUT_CAP_MC and use
> >>V4L2_OUTPUT_TYPE_ANALOG as the output type (again, a horrible outdated name and the
> >>spec is again out of date).
> >
> >I don't see any sense on distinguishing IN and OUT for MC. I mean: should
> >we ever allow that any driver to have their inputs controlled via V4L2 API,
> >and their outputs controlled via MC (or vice-versa)? I don't think so.
> >
> >Either all device inputs/outputs are controlled via V4L2 or via MC. So,
> >let's call it just V4L2_CAP_MC.
> >
> >>Regarding the name: should we use the name stored in struct video_device instead?
> >>That might be more descriptive.
> >
> >Makes sense to me.
> >
> >>Alternatively use something like "Media Controller Input".
> >
> >Yeah, we could do that, if V4L2_CAP_MC. if not, we can use the name
> >stored at video_device.
>
> Just to clarify: the V4L2_CAP_MC would indicated that the media controller
> is enabled in general? Or just for inputs and outputs?
I let Mauro and Hans to comment on their own behalf, but I think whatever is
communicated through the input IOCTLs should be applicable to inputs only.
The fact that the video device is a part of an MC graph could be conveyed
using a capability flag. Or by providing information on the media device
node, something that has been proposed earlier on. Either is out of the
scope of this patchset IMO, but should be addressed separately.
> If it is the first case, not necessarily the inputs/outputs are controlled
> via MC (we can still have a MC capable driver, but inputs/outputs controlled
> via V4L2 no? When the driver doesn't offer the necessary link controls via
> MC), then checking if V4L2_CAP_MC then use the name "Media Controller Input"
> is not enough.
> If it is the second case, then wouldn't it be better to name it
> V4L2_CAP_MC_IO ?
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
