On Mon, 03 Oct 2016 17:04:23 +0200, Pierre-Louis Bossart wrote: > > > >> For playback usages, the endpoints are started before the prepare > >> step, and valid audio data will be rendered with a delay that > >> cannot be recovered. > >> Worst-case the initial delay due to buffering of empty URBS can > >> be up to 12ms > > > This is really a fix unlike other patches in the series. > > Please split it from others, so that we can apply it easily. > > There was also additional discussions on this topic since I put this > together, not sure it makes sense to merge this patch at the moment. > In the Windows driver, the URBs can be submitted at a specific time, > which allows for synchronous starts of all endpoints (limited to the > 1ms frame resolution). In Linux we can't since the start time is owned > by the xhci driver and can't be modified by the class driver. I talked > with Mathias Nyman and Baolu Lu on this before the summer and of > course I became busy with other things. The short story is that there > is a wider problem with USB start and linking endpoints that should be > addressed as a single step. Maybe something to talk about at the > miniconference? Sure, why not. Now it's close to LPC and we won't reach to the solution soonish yet. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
