we try to set both in one ioctl, to the same value, which fails if not
both record and play direction support that many channels. (Having
more play than record channels is common these days.)
This does likely address part of the problem described in PR pkg/35444
by Mihai Chelaru, and it helped Matthew R. Green about half a year
ago -- see the thread in tech-misc in April.
doesn't obtain the ports, gain and balance related parameters.
Those generally require reading from the hardware and therefore are much
more expensive to obtain. Modify OSS emulation to use the new ioctl
where possible.
This reduces CPU usage of mplayer during mp3 playback with my Thinkpad
from 20% to < 1% and from 50% to 20% during Xvid playback.
Review and comments from jmcneill@
The optimized integer formula was supplied by Wolfgang Solfrank on
"tech-kern@netbsd.org". This fixes problems with e.g FreeBSD TV (fxtv),
RealPlayer-7.0 Beta 2 (PR pkg/10818) and KDE's "kscd".
encodings, too. (This is currently an issue with the eso(4) driver, which,
due to different byte orders in playing and recording directions, sets the
emulated flag for all 16-bit encodings, although it could be argued that this
is an unfortunate weakness of the query_encoding() interface.)
martin