Maupin, Chase wrote:
> All,
>
> Texas Instruments (TI) is working on the design for the V4L2 capture and
> display drivers for our next generation system-on-chip (SoC) processor and
> would like to solicit your feedback. Our new SoCs have been improved to
> allow for higher video resolutions and greater frame rates. To this end the
> display hardware has been moved to a separate processing block called the
> video processing subsystem (VPSS). The VPSS will be running a firmware image
> that controls the capture/display hardware and services requests from one or
> more host processors.
>
> Moving to a remote processor for the processing of video input and output
> data requires that commands to control the hardware be passed to this
> processing block using some form of inter-processor communication (IPC). TI
> would like to solicit your feedback on proposal for the V4L2 driver design to
> get a feel for whether or not this design would be accepted into the Linux
> kernel. To this end we have put together an overview of the design and usage
> on our wiki at
> http://wiki.davincidsp.com/index.php/Video_Processing_Subsystem_Driver_Design.
> We would greatly appreciate feedback from community members on the
> acceptability of our driver design.
>
> If you have additional questions or need more information please feel free to
> contact us (we have setup a mailing list at vpss_driver_des...@list.ti.com)
> so we can answer them.
>
Hi Chase,
I'm not sure if I got all the details on your proposal, so let me try to give my
understanding.
First of all, for normal usage (e.g. capturing a stream or sending an stream
to an output device), the driver should work with only the standard V4L2 API.
I'm assuming that the driver will provide this capability.
I understand that, being a SoC hardware, there are much more that can be done
than just doing the normal stream capture/output, already supported by V4L2 API.
For such advanced usages, we're open to a proposal to enhance the existing API
to support the needs. There are some important aspects that need to be
considered
when designing any Linux userspace API's:
1) kernel-userspace API's are forever. So, they need to be designed in
a way that new technology changes won't break the old API;
2) API's are meant to be generic. So, they needed to be designed in a
way
that, if another hardware with similar features require an API, the planned one
should fit;
3) The API's should be, as much as possible, independent of the hardware
architecture. You'll see that even low-level architecture dependent stuff, like
bus drivers are designed in a way that they are not bound to a particular
hardware,
but instead provide the same common methods to interact with the hardware to
other
device drivers.
That's said, it would be interesting if you could give us a more deep detail on
what kind of functionalities and how do you think you'll be implementing them.
--
Cheers,
Mauro
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