Lennart Poettering wrote: > On Fri, 23.01.09 18:56, Clemens Ladisch (clemens@xxxxxxxxxx) wrote: > > Instead of writing a callback in the USB driver to compute the time > > until the next underrun, I'd rather rip out that fast start code. (Done.) > > So, no kernel computation is needed. :-) > > While I think it would be good not have this kind of double-buffering > I wonder if this is really future-proof. i.e. can this done with every > driver that uses 'fast starts'? Yes, because the USB driver was the only one that did this. There are other drivers that use double-buffering (and the USB driver still does), but there the playback speed does not change, i.e., the stream is not more underrun-prone when starting. > > * For many devices (legacy ISA, etc.), we just don't know the correct > > value. > > But it should be possible to pick a safe boundary, shouldn't it? In theory, the _safe_ boundary is one period. In practice, ISA devices cannot afford to prefetch much data due to the low bus bandwidth, so one (frame) should be OK. (And we _know_ devices that do whole-period double-buffering because the code is right there in the driver.) Best regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
