Hi Sakari On Sat, Jul 08, 2023 at 12:13:17PM +0000, Sakari Ailus wrote: > Hi Jacopo, > > On Mon, Jul 03, 2023 at 09:47:37AM +0200, Jacopo Mondi wrote: > > Hi Sakari > > > > On Fri, Jun 30, 2023 at 11:43:35PM +0300, Sakari Ailus wrote: > > > Document how internal pads are used on source routes. > > > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > > --- > > > .../userspace-api/media/v4l/dev-subdev.rst | 20 +++++++++++++++++++ > > > 1 file changed, 20 insertions(+) > > > > > > diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst > > > index a4f1df7093e8..5a46c9a9d352 100644 > > > --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst > > > +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst > > > @@ -551,6 +551,26 @@ A stream at a specific point in the media pipeline is identified by the > > > sub-device and a (pad, stream) pair. For sub-devices that do not support > > > multiplexed streams the 'stream' field is always 0. > > > > > > +.. _v4l2-subdev-source-routes: > > > + > > > +Source routes > > > +^^^^^^^^^^^^^ > > > > I always found the concept of source routes a bit confusing, should we > > instead just present internal pads ? > > > > > + > > > +Cases where a single sub-device pad is a source of multiple streams are special > > > +as there is no external sink pad for such a route. In those cases, the sources > > > +of the streams are indicated by source routes that have an internal source pad > > > +as the sink pad of such a route. Internal source pads have the > > > +:ref:`MEDIA_PAD_FL_INTERNAL <MEDIA-PAD-FL-INTERNAL>` and ``MEDIA_PAD_FL_SINK`` > > > +pad flags set. > > > > All this last part is a little bit hard to parse, not your fault but > > the fact "internal source pads" are actually "SINK" pads is a bit > > confusing ? > > > > Can we remove the "source route" concept to avoid mixing source/sink ? > > > > This can be rewritten as > > > > Internal pads > > ^^^^^^^^^^^^^ > > > > Cases where a single sub-device pad is a source of multiple streams are special > > as there is no external sink pad for such a route. A typical example is a > > sensor device which produces a video stream and a metadata stream of > > embedded data. To support such cases internal pads are introduced as > > sink pads of such internally generated streams. > > Internal source pads have the :ref:`MEDIA_PAD_FL_INTERNAL > > <MEDIA-PAD-FL-INTERNAL>` and ``MEDIA_PAD_FL_SINK`` pad flags set. > > > > > +Internal source pads have all the properties of a sink pad in such case, > > > > Also here, "Internal source pads" are actually sinks :) > > > > I would drop "source" from "Internal source pads" > > How about this (compared to the patch): > > diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst > index 5a46c9a9d352..9d544a29e78a 100644 > --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst > +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst > @@ -553,21 +553,23 @@ multiplexed streams the 'stream' field is always 0. > > .. _v4l2-subdev-source-routes: > > -Source routes > -^^^^^^^^^^^^^ > - > -Cases where a single sub-device pad is a source of multiple streams are special > -as there is no external sink pad for such a route. In those cases, the sources > -of the streams are indicated by source routes that have an internal source pad > -as the sink pad of such a route. Internal source pads have the > -:ref:`MEDIA_PAD_FL_INTERNAL <MEDIA-PAD-FL-INTERNAL>` and ``MEDIA_PAD_FL_SINK`` > -pad flags set. > - > -Internal source pads have all the properties of a sink pad in such case, > -including formats and selections. The format in this case is the source format > -of the stream. An internal pad always has a single stream only (0). > - > -Generally source routes are not modifiable but they can be activated and > +Internal pads and source routes > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + > +Cases where a single sub-device source pad is traversed by multiple streams one > +or more of which originate from within the sub-device itself are special as > +there is no external sink pad for such routes. In those cases, the sources of "external" made me think of "a different entity". Can we just drop it or am I too easy to confuse ? > +the internally generated streams are indicated by internal pads, pads which have s/indicated by/represented by/ ? 'internal pads, pads...' or /internal pads, which are sink pads with the :ref:`MEDIA_PAD_FL_INTERNAL` <MEDIA-PAD-FL-INTERNAL> pad flag set.' and drop the "on the sink pad of the route" ? > +a :ref:`MEDIA_PAD_FL_INTERNAL` <MEDIA-PAD-FL-INTERNAL> pad flag set on the sink > +pad of the route. A typical use case for these is a camera sensor device which > +produces a pixel data stream and an embedded data stream. This case is represented with two internal sink pads for the video and the data streams and a single multiplexed source pad that connects to the next entity in the pipeline. > + > +Internal pads have all the properties of an external pad, including formats and > +selections. The format in this case is the source format of the stream. An > +internal pad always has a single stream only (0). > + > +/Source routes/ are routes from an internal sink pad to a(n external) source > +pad. Generally source routes are not modifiable but they can be activated and > deactivated using the :ref:`V4L2_SUBDEV_ROUTE_FL_ACTIVE > <v4l2-subdev-routing-flags>` flag, depending on driver capabilities. If you want to keep the part about source routes, this form is ok with me! > > I'll also check the ACTIVE route flag, it wasn't merged with the rest of > the Tomi's streams series. > > -- > Kind regards, > > Sakari Ailus
