On Thu, Oct 29, 2015 at 06:44:12AM -0700, Caleb Crome wrote: > > Reported by user space? Are you saying that's an ALSA underrun in > > the user space, not a hardware underrun reported by the IRQ in the > > driver? They are quite different. ALSA underrun comes from the DMA > > buffer gets underrun while the other one results from FIFO feeding > > efficiency. For ALSA underrun, enlarging the playback period size > > and period number will ease the problem: > Sometimes they happen at the same time. So, I run aplay, and all is The 'they' is indicating ALSA underrun + hardware underrun or ALSA underrun + channel slip? It's not quite logical for a channel slip resulting from an ALSA underrun as it should restart by calling the trigger() functions in DAI drivers IIRC. > fine. Then the user space app will underrun, and then I look at the > scope, and the channels have slipped. So somehow the start/restart > after the underrun is not always perfect I guess. > Is there any mechanism for the DMA fifo underruns to be reported back > to user space? There certainly should be, because the consequences No. The release from Freescale official tree has a reset procedure applied to ESAI underrun but not SSI but I guess you may want to refer to that. > are catastrophic, yet the user space app goes on as if everything is > just great. Much, much worse than the underrun that is reported (i.e. > a skip in audio is bad but sometimes tolerable. A channel slip is > permanent and absolutely intolerable). _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
