On Tue, 13 Feb 2018 15:56:08 +0100, Wischer, Timo (ADITG/ESB) wrote: > > Hello Takashi, > > > This has nothing to do with the reported position. If this happens, > it simply means an XRUN. You should report the error instead. > > When the ALSA buffer is full and the JACK daemon is requesting exactly the amount of samples of the buffer size > I do not see an under run here. > After such an operation the ALSA buffer is empty > but the JACK daemon has not read more samples than available. The backend has nothing to do with such a case. This happens only when the application uses periods=1, and then it implies that the application must know of the situation. The ioplug simulates the say the hardware device would behave. It notifies the period elapse via file-descriptor and it reports the DMA ring-buffer position. The ring buffer is between 0 to buffer size, you must not exceed it in the reporting. Takashi > Exactly in this case we would increment the hw_ptr += buffer_size > but this would not be recognized by the ALSA library > when we are using a wrap around of buffer_size. > > > > No, the ioplug backend has to report the position from 0 to buffer_size. > > I know but I think the ioplug API implementation has possibly to be changed to allow exactly such use cases > as described above. > > Or do you have another idea how to report such a hw_ptr change? > > Best regards > > Timo Wischer > > Advanced Driver Information Technology GmbH > Engineering Software Base (ADITG/ESB) > Robert-Bosch-Str. 200 > 31139 Hildesheim > Germany > > Tel. +49 5121 49 6938 > Fax +49 5121 49 6999 > twischer@xxxxxxxxxxxxxx > > ADIT is a joint venture company of Robert Bosch GmbH/Robert Bosch Car Multimedia GmbH and DENSO Corporation > Sitz: Hildesheim, Registergericht: Amtsgericht Hildesheim HRB 3438 > Geschäftsführung: Wilhelm Grabow, Ken Yaguchi > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
