On Sat, Mar 25, 2017 at 02:21:13AM +0530, Ughreja, Rakesh A wrote: > >> >Are these workarounds needed for the legacy driver? > >> >If yes, which chips require it? > >> > > >> > >> Yes, these are needed in legacy driver as well. > >> From SKL and BXT onwards, it is needed. > > > >OK, thanks for confirmation. > > > >Now, from what I read in the above, is the workaround required *only* > >after the interrupt is generated? 20us delay isn't so cheap, and we > >tend to inquire PCM positions often. If the workaround is needed only > >after the PCM period elapse, we can set some flag in the irq handler > >and apply the workaround only when necessary. > > > > Yes, Takashi the workaround is required only in the period elapsed > interrupt. In some cases the DMA Position updates are delayed and so > when the period elapsed interrupt occurs the wait_for_avail thinks that > one period worth of data is not available and so returns only on the > next period elapsed interrupt. This creates problem for 2 periods > playback/capture streams. > > So even in the period elapsed interrupt the wait is required only if the > position is less than the period boundary. Hi Takashi, So we need this for 2 periods when the device is in irq mode. Not for other cases. ie SKL_PLUS.. But have you seen any user reports on this till now. -- ~Vinod _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
