Re: PCIe capture driver

[Hans Verkuil <hverkuil@xs4all.nl>]

On 10/27/2015 02:04, Ran Shalit wrote:
> On Mon, Oct 26, 2015 at 1:46 PM, Steven Toth <stoth@kernellabs.com> wrote:
>>> No, use V4L2. What you do with the frame after it has been captured
>>> into memory has no relevance to the API you use to capture into memory.
>>
>> Ran, I've built many open and closed source Linux drivers over the
>> last 10 years - so I can speak with authority on this.
>>
>> Hans is absolutely correct, don't make the mistake of going
>> proprietary with your API. Take advantage of the massive amount of
>> video related frameworks the kernel has to offer. It will get you to
>> market faster, assuming your goal is to build a driver that is open
>> source. If your licensing prohibits an open source driver solution,
>> you'll have no choice but to build your own proprietary API.
>>
>> --
>> Steven Toth - Kernel Labs
>> http://www.kernellabs.com
> 
> Hi,
> 
> Thank you very much for these valuable comments.
> If I may ask one more on this issue:
> Is there an example in linux tree, for a pci device which is used both
> as a capture and a display device ? (I've made a search but did not
> find any)
> The PCIe device we are using will be both a capture device and output
> video device (for display).

The cobalt driver (drivers/media/pci/cobalt) does exactly that: multiple HDMI inputs and an optional HDMI output (through a daughterboard).

Please note: using V4L2 for an output only makes sense if you will be outputting video, if the goal is to output a graphical desktop then the drm/kms API is much more suitable.

Regards,

	Hans