Two things the last pass looked at and left, now measured on hardware by the new
audio/blocking/vaudio and audio/blocking/overhead.
sceVaudioChRelease is not shaped like the Output2 and SRC releases. It hands the
channel a null pointer first, which waits for a buffer to finish, so it blocks for
one buffer and returns 0 where the others would refuse - and the buffer is played
out instead of being dropped, which is what we were doing. The reservation goes
now rather than when the drain finishes: the caller is parked either way and gets
the same answer at the same time, and the buffers keep playing because the mixer
does not look at the reservation.
The same test turned up two more: a *failed* sceVaudioChReserve still marks vaudio
reserved, so a caller that lost the channel to Output2 is told 0x80000021 next
time until a release clears it; and sceVaudioChRelease ignores that flag entirely
and releases whatever holds the SRC channel, which pspautotests already called the
"wrong release".
The flat 10000 cycles charged to every Output2 and SRC output turns out to be
right only for the refused case. Every other outcome ends up querying the codec
and costs over 100us on hardware, including finding the channel unreserved, so
those now cost 25000. Mixer channels are the other way round - cheap to refuse,
expensive on the one output that starts the DMA - so that charge moved to the DMA
start. F1 2009 behaves identically and Burnout Dominator's mixed output is
bit-identical to before.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
