At Sun, 26 Apr 2009 11:42:14 -0400, Jon Smirl wrote: > > On Sun, Apr 26, 2009 at 7:14 AM, Takashi Iwai <tiwai@xxxxxxx> wrote: > > At Sat, 25 Apr 2009 17:28:55 -0400, > > Jon Smirl wrote: > >> > >> These new patches have broken audio support on the mpc5200.... > > > > Then the lowlevel callbacks are likely wrong :) > > > >> They assume that the hardware is capable of telling where the DMA > >> engine is in the middle of an operation. > > > > Well, nothing new by these patches. The original PCM core > > implementation has been designed in that way. These changes may check > > some bogus value more strictly. > > > > If the hardware doesn't support it, it needs report at least some > > "sane" value; i.e. it must not be over the real position, but not > > below the previous pointer. > > > > > In the worst case, the driver just needs to report the same position > > at the previous period boundary until the next > > snd_pcm_period_elapsed(). > > That's doesn't work anymore. The PCM code is using jiffies to estimate > where the pointer needs to be. > I used the same jiffies to fake up a hardware position. Hrm, then it's a breakage. The quantum position must be still supported. Jaroslav, could you check that? It's your new code... As an easy workaround, we can give a pcm info flag to indicate that the driver doesn't provide the continuous DMA position. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
