Re: [PATCH v7 1/7] media: add glossary.rst with a glossary of terms used at V4L2 spec

[Mauro Carvalho Chehab <mchehab@s-opensource.com>]

Em Fri, 6 Oct 2017 13:22:29 +0300
Sakari Ailus <sakari.ailus@iki.fi> escreveu:

> > +    Bridge driver
> > +	The same as V4L2 main driver.  
> 
> Not all V4L2 main drivers can be bridge drivers. Mem-to-mem devices, for
> instance. How about:
> 
> A driver for a device receiving image data from another device (or
> transmitting it to a sub-device) controlled by a sub-device driver. Bridge
> drivers typically act as V4L2 main drivers.

That is not true for some device drivers we have.

The GSPCA drivers are bridge drivers, but they don't use any sub-device
(well, it should, but nobody will redesign it, as the efforts would
be huge, for a very little gain). Also uvcdriver doesn't need sub-device
drivers, as the camera's internal firmware does the interface with the
sensors.

We could, instead define it as:

    Bridge driver
	A driver that provides a bridge between the CPU's bus to the
	data and control buses of a media hardware. Often, the
	bridge driver is the same as V4L2 main driver.

Thanks,
Mauro