Re: [PATCH v10 3/4] media: docs: add glossary.rst with common terms used at V4L2 spec

From: Mauro Carvalho Chehab
Date: Fri Aug 28 2020 - 05:11:07 EST


Em Thu, 27 Aug 2020 14:08:11 +0300
Sakari Ailus <sakari.ailus@xxxxxx> escreveu:

> > + MC-centric
> > + :term:`V4L2 hardware` that requires a :term:`MC API`.
> > +
> > + Such hardware have ``V4L2_CAP_IO_MC`` device_caps field set
> > + (see :ref:`VIDIOC_QUERYCAP`).
> > +
> > + See :ref:`v4l2_hardware_control` for more details.
>
> I think this should be documented as referring to drivers, for it's a
> property of a driver, not hardware.
>
> There is hardware that better fits for MC-enabled drivers but still has
> V4L2-centric driver written for it. The matter is further complicated by
> e.g. raw camera systems that may consist of several different kinds of
> devices, including external ISPs.
>
> Say, a simple raw sensor + a CSI-2 receiver would fit for V4L2-centric
> model well, but add a more complex sensor or that external ISP and that no
> longer is the case. The CSI-2 receiver is still the same in both cases
> though.
>
> Similar comment on video-node-centric.

I guess I got what you meant. I'm folding it with the following diff:

diff --git a/Documentation/userspace-api/media/glossary.rst b/Documentation/userspace-api/media/glossary.rst
index 45f0933e03c0..023bb561c406 100644
--- a/Documentation/userspace-api/media/glossary.rst
+++ b/Documentation/userspace-api/media/glossary.rst
@@ -138,9 +138,9 @@ Glossary
See :ref:`media_controller`.

MC-centric
- :term:`V4L2 hardware` that requires a :term:`MC API`.
+ :term:`V4L2 hardware` device driver that requires :term:`MC API`.

- Such hardware have ``V4L2_CAP_IO_MC`` device_caps field set
+ Such drivers have ``V4L2_CAP_IO_MC`` device_caps field set
(see :ref:`VIDIOC_QUERYCAP`).

See :ref:`v4l2_hardware_control` for more details.
@@ -203,9 +203,9 @@ Glossary
:term:`bridge driver`. See :ref:`subdev`.

Video-node-centric
- V4L2 hardware that doesn't require a media controller to be used.
+ V4L2 device driver that doesn't require a media controller to be used.

- Such hardware have the ``V4L2_CAP_IO_MC`` device_caps field unset
+ Such drivers have the ``V4L2_CAP_IO_MC`` device_caps field unset
(see :ref:`VIDIOC_QUERYCAP`).

V4L2 Sub-device API


Thanks,
Mauro