On Thu, 28 Jul 2016 22:33:31 +0200, Lars-Peter Clausen wrote: > > On 07/28/2016 05:46 AM, Vinod Koul wrote: > > On Wed, Jul 27, 2016 at 10:22:41PM +0200, Takashi Iwai wrote: > >> On Wed, 27 Jul 2016 20:22:33 +0200, > >> Mark Brown wrote: > >>> > >>> On Wed, Jul 27, 2016 at 08:11:49PM +0200, Takashi Iwai wrote: > >>> > >>>> I'm wondering whether it's a better option to block the unbind > >>>> behavior, either in driver base (allowing to return an error) or in > >>>> the sound side (waiting in remove() until the sane point). > >>> > >>> That's certainly going to be a lot easier and part of the reason it's > >>> never been looked at much is that (unlike USB) there's very little > >>> reason why an ASoC sound card would ever be hotplugged - even in > >>> development these days the normal development flow involves rebooting. > > > > I agree, it makese no sense for devices to be hotplugged. And for > > developement flows people can do rmmond and insmod. That works fine! > > I don't agree. In my opinion hot-plug is an essential feature of a > modern device driver framework and if ASoC wants to claim to fall in > this category we ought to support it. Hotplug is something that always > pops up sooner or later. E.g. if someone puts a ASoC supported CODEC on > a hot-pluggable device (maybe USB) we don't want to duplicate the code, > but be able to reuse. > > One area that e.g. requires hot-plug/-unplug and were ASoC supported > devices are used is embedded development boards that support shields and > devicetree overlays. Like e.g. RPI and similar. > > The reason why we don't support hot-unplug in ASoC at the moment is > because it is not trivial to implement and nobody has cared enough yet. > > But if somebody wants to and has the resources to implement this we > should not discourage this. > > I'd very much prefer to have proper hot-plug support instead of > prohibiting unbinding even on systems that do not require hot-plug > support normally. It's a much cleaner solution. Well, but hot-unplugging only a component like codec would be needed in a real scenario? It's a different story from the hotplug in the card level. Takashi
