Hi,
On 08/17/2012 04:44 PM, Mauro Carvalho Chehab wrote:
Em 17-08-2012 07:35, Hans Verkuil escreveu:
Hi all,
I've prepared a presentation for the upcoming workshop based on my RFC and the comments I received.
It is available here:
http://hverkuil.home.xs4all.nl/presentations/v4l2-workshop-2012.odp http://hverkuil.home.xs4all.nl/presentations/v4l2-workshop-2012.pdf
Attendees of the workshop: please review this before the workshop starts. I want to go through this list fairly quickly (particularly slides 1-14) so we can have more time for other topics.
With regards to "tuner ownership" topic, I think it should be handled on a more generic way. There are several parts of the media devices that could be owned by more than one device type:
- tuners;
- i2c buses;
- DMA engines;
- device-internal buses;
...
So, devices that share the same resource for more than one different type of access (radio, analog TV, digital TV, subdev API), should be locking the used resources.
Right, the problem the tuner discussion talks about is not as much, how to do the locking, as about *when* to do the locking, which is very much tuner specific. The problem is most apps don't use the priority API, so we need some way to figure out when an app should become the tuner "owner" and lock the tuner on its behalf, so that other apps cannot mess with it breaking the functionality of the first app to become the owner.
Regards,
Hans