On Tue, 20 Dec 2016, at 03:14 PM, Ahmed S. Darwish wrote: > Hi Tanu, > > On Sun, Dec 18, 2016 at 08:59:58PM +0200, Tanu Kaskinen wrote: > > On Sat, 2016-12-17 at 01:43 +0200, Ahmed S. Darwish wrote: > > > # Note: Documentation of `pa_stream_begin_write(stream, &buf, &nbytes)' > > > # suggests to pass nbytes = -1. Doing so though lends to a huge returned > > > # nbytes values. Calling a pa_stream_write() with such values chokes the > > > # stream: making it go silent and not produce any further write-callback > > > # events. > > > # > > > # Is this a problem in usage pattern, or a bug? > > > > Sounds like a bug. Trying to write more than buffer_attr.maxlength > > bytes at once would be expected to cause some kind of problems, but I > > don't think that's the case here. The returned nbytes value is 64k, > > isn't it? pacat uses the default maxlength, and the default maxlength > > is 4M, so nbytes is nowhere near that limit. As long as maxlength isn't > > exceeded, any "extra" audio should just get buffered in the stream > > buffer at the server side. > > > > Yeah; sounds like a bug in the write stream indeed. > > In the command below, (second pacat): > > ./src/pacat -r --latency-msec=4 | ./src/pacat --latency-msec=4 > > When using "writable" values from pa_stream_writable_size(), we > get the following, valid, sequence: > > ++ STDIN callback: mute! stream writable = 0 > @@ WRITE callback: Re-enable STDIN events > <-- Small writable val; appropriate for requested small latency --> > @@ STDIN callback: stream writable size = 192 > ** Writing 192 bytes; frame len = 4 > > ++ STDIN callback: mute! writable = 0 > @@ WRITE callback: Re-enable STDIN events > <-- Small writable val; appropriate for requested small latency --> > @@ STDIN callback: stream writable size = 192 > ** Writing 192 bytes; frame len = 4 > > ... Sequence endlessly repeated ... > > BUT when using "writable" values from pa_stream_begin_read(), with > "writable = (size_t)-1" as the documentation recommends, we get > that sequence instead: > > @@ WRITE callback: Re-enable STDIN events > @@ STDIN callback: stream writable size = 65472 <== 64K indeed > ** Writing 2112 bytes; frame len = 4 > ++ STDIN callback: mute! writable = 0 > > <-- COMPLETE silence! - no more stream write callback events --> > > Hopefully not a new blocker, but if you agree with the assessment > above, I'll submit a bug to be tracked for v11. Is that a regression? -- Arun
