On Thu, 16 Apr 2009, Dongsoo, Nathaniel Kim wrote: > Hello Guennadi, > > On Thu, Apr 16, 2009 at 9:06 PM, Guennadi Liakhovetski > <g.liakhovetski@xxxxxx> wrote: > > 3. you open videoX, one "default" camera gets activated immediately - not > > all applications issue S_INPUT, so, there has to be a default. > > 4. if an S_INPUT is issued, you have to verify, whether any camera is > > currently active / capturing, if none - switch to the requested one, if > > one is active - return -EBUSY. > > 5. reference-counting and guaranteeing consistency is more difficult, as > > well as handling camera driver loading / unloading. > > Oops I forgot to say that we need to enforce legacy v4l2 applications > to use VIDIOC_S_INPUT after opening device. > And every S_INPUT issuing should come after G_INPUT like every "set" > API in v4l2. Hm? Does the API require it? If not, I don't think we should inforce it. And what do you mean "legacy v4l2 applications" - which applications are not "legacy"? > > So, I would say, your approach adds complexity and asymmetry. Can it be > > that one camera client has several inputs itself? E.g., a decoder? In any > > case, I wouldn't do this now, if we do decide in favour of your approach, > > then only after the v4l2-device transition, please. > > > > Of course. I didn't mean to disturb your transition job. Please do > your priority job first. > > And about camera client with several inputs question, I will say that > almost every 3G UMTS phone has dual camera on it. And we can consider > every 3G UMTS smart phones have dual camera on it with soc camera > solution. No, sorry, this wasn't my question. By "client" I meant one camera or decoder or whatever chip connects to a camera host. I.e., if we have a single chip with several inputs, that should logically be handled with S_INPUT ioctl, this would further add to the confusion of using different inputs on one video device to switch between chips or inputs / functions on one chip. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
