I've been reading Lennart's article on glitch free audio.... On my scatter/gather DMA hardware I generate an interrupt at the end of each period. On the last period this causes ALSA to issue a trigger(STOP). However, there is a latency from when that interrupt is generated and when ALSA does the trigger(STOP). During that latency my hardware starts playing the next buffer (which contains stale data). Playing stale data causes a noise burst. I fixed this by programming my DMA hardware to not overrun appl_ptr. There's another solution. ALSA already knows the stream ends mid-period and pads out the partial period with silence. If it simply padded out the next period with silence too the overrun problem would become non-audible and there would time to process trigger(STOP). If padding out two periods at end of stream is possible, it then becomes possible for me to turn off interrupts in my audio driver. -- Jon Smirl jonsmirl@xxxxxxxxx _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
