On 07/31/2012 02:26 PM, Guennadi Liakhovetski wrote: >>>> But should we allow host probe() to succeed if the sensor isn't present ? >>> >>> I think we should, yes. The host hardware is there and functional - >>> whether or not all or some of the clients are failing. Theoretically >>> clients can also be hot-plugged. Whether and how many video device nodes >>> we create, that's a different question. >> >> I think I can agree with you on this (although I could change my mind if this >> architecture turns out to result in unsolvable technical issues). That will >> involve a lot of work though. > > There's however at least one more gotcha that occurs to me with this > approach: if clients fail to probe, how do we find out about that and turn > clocks back off? One improvement to turning clocks on immediately in Hmm, wouldn't it be the client that turns a clock on/off when needed ? I'd like to preserve this functionality, so client drivers can have full control on the power up/down sequences. While we are trying to improve the current situation... > host's probe() is to only do it in a BUS_NOTIFY_BIND_DRIVER notifier. But > how do we find out, that probing failed? No notifier is called in this > case. We could use a time-out, but that's ugly. I think, we could ever > request a new notifier for this case. We could also require client drivers > to call a V4L2 function in this case, but that's not very pretty either. -- Regards, Sylwester -- 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
