On Mon, Nov 27, 2017 at 02:48:50PM +0530, Vinod Koul wrote: > On Mon, Nov 27, 2017 at 07:59:40AM +0000, Charles Keepax wrote: > > > > > Apologies for the long and slightly vague comment, but I guess my > > > > question is do you have a thought on how drivers should know when > > > > it is safe to communicate with a SoundWire device? > > > > > > IMO it is safe to communicate with SoundWire device when the Slave > > > status is ATTACHED. In any case bus will report error if it is not able > > > to communicate with SoundWire device. > > > > Yeah I guess my point here is that there is currently no way in > > this SoundWire framework for the slave driver to know if the > > device is attached or not, unless I am missing something? There > > are calls by which the master can inform the framework, but > > nothing to pass that on to the slave driver. > > Nope, as Sanyog pointed out there are deterministic ways for Slave > driver to find out. We can do that by: > a) check the slave->status and communicate only if status is SDW_SLAVE_ATTACHED > b) Implement sdw_slave_ops->update_status() which is invoked by Bus on any > status changes. > > So to summarize, for a Slave driver during the probe, if the status is not > SDW_SLAVE_ATTACHED it should not communicate and should implement > sdw_slave_ops->update_status and attempt IO when this callback gets invoked > with SDW_SLAVE_ATTACHED status. > > Does that clarify and solve the problem. > Ok apologies looks like this was my bad sorry for missing those. That does indeed seem fine. Thanks, Charles _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
