Re: [Xen-devel] [alsa-devel] [PATCH RESEND1 00/12] ALSA: vsnd: Add Xen para-virtualized frontend driver

2017-09-05 Thread Clemens Ladisch
Oleksandr Andrushchenko wrote: >>> We understand that emulated interrupt on the frontend side is completely not >>> acceptable Allow me to expand on that: Proper synchronization requires that the exact position is communicated, not estimated. Just because the nominal rate of the stream is known

Re: [Xen-devel] [alsa-devel] [PATCH 08/11] ALSA: vsnd: Add timer for period interrupt emulation

2017-08-07 Thread Clemens Ladisch
Oleksandr Andrushchenko wrote: > Front sound driver has no real interrupts, so > playback/capture period passed interrupt needs to be emulated: > this is done via timer. Add required timer operations, > this is based on sound/drivers/dummy.c. A 'real' sound card use the interrupt to synchronize th

Re: [Xen-devel] [alsa-devel] [PATCH 08/11] ALSA: vsnd: Add timer for period interrupt emulation

2017-08-07 Thread Clemens Ladisch
Oleksandr Andrushchenko wrote: > On 08/07/2017 01:27 PM, Clemens Ladisch wrote: >> You have to implement period interrupts (and the .pointer callback) >> based on when the samples are actually moved from/to the backend. > > Do you think I can implement this in a slightly diffe

Re: [Xen-devel] [alsa-devel] [PATCH 08/11] ALSA: vsnd: Add timer for period interrupt emulation

2017-08-07 Thread Clemens Ladisch
Oleksandr Andrushchenko wrote: > On 08/07/2017 04:11 PM, Clemens Ladisch wrote: >> How does that interface work? > > For the buffer received in .copy_user/.copy_kernel we send > a request to the backend and get response back (async) when it has copied > the bytes into HW/mix