On Mon, Jul 1, 2013 at 9:06 PM, Clemens Ladisch <clemens@xxxxxxxxxx> wrote: > Ming Lei wrote: >> On Sun, Jun 30, 2013 at 11:02 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >>> Naturally, under normal circumstances this won't matter, because >>> underruns shouldn't occur. But I know from experience that people try >>> to push the latency as far down as they can, which increases the >>> likelihood of underruns. >> >> I understand the latency is effected by packet count in one URB, >> and it shouldn't be related with URB count, > > This is true only when capturing. For playback, the latency is the > length of the entire pipeline. For playback, every URB submitted is added into hw table immediately, then the data will be played to speaker. I don't understand why the latency is the entire pipeline. If you submitted a bit more URBs, underruns shouldn't happen at all. Could you explain it in a bit detail? Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
