Re: [PATCH v8 41/55] [media] DocBook: update descriptions for the media controller entities

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hello,

On Friday 11 September 2015 15:13:30 Hans Verkuil wrote:
> On 09/06/2015 02:03 PM, Mauro Carvalho Chehab wrote:
> > Cleanup the media controller entities description:
> > - remove MEDIA_ENT_T_DEVNODE and MEDIA_ENT_T_V4L2_SUBDEV entity
> >   types, as they don't mean anything;
> > - add MEDIA_ENT_T_UNKNOWN with a proper description;
> > - remove ALSA and FB entity types. Those should not be used, as
> >   the types are deprecated. We'll soon be adidng ALSA, but with
> >   a different entity namespace;
> > - improve the description of some entities.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> > 
> > diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml
> > b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml index
> > 32a783635649..bc101516e372 100644
> > --- a/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml
> > +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml
> > @@ -179,70 +179,65 @@
> >          <colspec colname="c2"/>
> >  	<tbody valign="top">
> >  	  <row>
> > -	    <entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry>
> > -	    <entry>Unknown device node</entry>
> > +	    <entry><constant>MEDIA_ENT_T_UNKNOWN</constant> and
> > <constant>MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN</constant></entry> +	   
> > <entry>Unknown entity. That generally indicates that
> > +	    a driver didn't initialize properly the entity, with is a Kernel
> > bug</entry>> 
> >  	  </row>
> 
> I'm wondering: if userspace should never see an unknown entity, wouldn't it
> be better to move these UNKNOWN defines out of the public header to a kernel
> header and drop this from the documentation?

And shouldn't the bug be caught in kernelspace before it reaches the user ?

> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_V4L2_VIDEO</constant></entry>
> > -	    <entry>V4L video, radio or vbi device node</entry>
> > +	    <entry>V4L video streaming input or output entity</entry>
> >  	  </row>
> > -	  <row>
> > -	    <entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry>
> > -	    <entry>Frame buffer device node</entry>
> > +	    <entry><constant>MEDIA_ENT_T_V4L2_VBI</constant></entry>
> > +	    <entry>V4L VBI streaming input or output entity</entry>
> >  	  </row>
> > -	  <row>
> > -	    <entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry>
> > -	    <entry>ALSA card</entry>
> > +	    <entry><constant>MEDIA_ENT_T_V4L2_SWRADIO</constant></entry>
> > +	    <entry>V4L Sofware Digital Radio (SDR) streaming input or output
> > entity</entry>
>
> s/Sofware/Software/
> 
> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_DVB_DEMOD</constant></entry>
> > -	    <entry>DVB frontend devnode</entry>
> > +	    <entry>DVB demodulator entity</entry>
> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_DVB_DEMUX</constant></entry>
> > -	    <entry>DVB demux devnode</entry>
> > +	    <entry>DVB demux entity. Could be implemented on hardware or in
> > Kernelspace</entry>

s/Could be/Can be/

> s/on/in/
> 
> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_DVB_TSOUT</constant></entry>
> > -	    <entry>DVB DVR devnode</entry>
> > +	    <entry>DVB Transport Stream output entity</entry>
> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_DVB_CA</constant></entry>
> > -	    <entry>DVB CAM devnode</entry>
> > +	    <entry>DVB Conditional Access module (CAM) entity</entry>
> >  	  </row>
> >  	  <row>
> >  	    
<entry><constant>MEDIA_ENT_T_DVB_DEMOD_NET_DECAP</constant></entry>
> > -	    <entry>DVB network devnode</entry>
> > -	  </row>
> > -	  <row>
> > -	    <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry>
> > -	    <entry>Unknown V4L sub-device</entry>
> > +	    <entry>DVB network ULE/MLE desencapsulation entity. Could be
> > implemented on hardware or in Kernelspace</entry>

s/Could be/Can be/

> s/on/in/
> 
> Hmm, is desencapsulation correct? Could it be 'de-encapsulation' instead? It
> looks weird.
>
> >  	  </row>
> >  	  <row>
> >  	    
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry>
> > -	    <entry>Video sensor</entry>
> > +	    <entry>Camera video sensor entity</entry>

s/video sensor/image sensor/

> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry>
> > -	    <entry>Flash controller</entry>
> > +	    <entry>Flash controller entity</entry>
> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry>
> > -	    <entry>Lens controller</entry>
> > +	    <entry>Lens controller entity</entry>
> >  	  </row>
> >  	  <row>
> >  	    
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_DECODER</constant></entry>
> > -	    <entry>Video decoder, the basic function of the video decoder is 
to
> > -	    accept analogue video from a wide variety of sources such as
> > +	    <entry>Analog video decoder, the basic function of the video 
decoder
> > +	    is to accept analogue video from a wide variety of sources such 
as
> >  	    broadcast, DVD players, cameras and video cassette recorders, in
> > -	    either NTSC, PAL or HD format and still occasionally SECAM, 
separate
> > -	    it into its component parts, luminance and chrominance, and 
output
> > +	    either NTSC, PAL, SECAM or HD format, separating the stream
> > +	    into its component parts, luminance and chrominance, and output
> >  	    it in some digital video standard, with appropriate embedded 
timing
> >  	    signals.</entry>

Does timing signals refer to synchronization signals ? They don't have to be 
embedded, do they ?

> >  	  </row>
> >  	  <row>
> >  	    <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_TUNER</constant></entry>
> > -	    <entry>TV and/or radio tuner</entry>
> > +	    <entry>Digital TV, analog TV, radio and/or software radio
> > tuner</entry>> 
> >  	  </row>
> >  	</tbody>
> >        </tgroup>

-- 
Regards,

Laurent Pinchart