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author | hselasky <hselasky@FreeBSD.org> | 2015-03-26 10:25:15 +0000 |
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committer | hselasky <hselasky@FreeBSD.org> | 2015-03-26 10:25:15 +0000 |
commit | bc8d9c80f509c57810a7baabb93803620f6d88dd (patch) | |
tree | 87afefc311f0b2176ffdbe510919f60311464f45 /share | |
parent | 457dafa988454b0057a86653c0afa7e95e68260b (diff) | |
download | FreeBSD-src-bc8d9c80f509c57810a7baabb93803620f6d88dd.zip FreeBSD-src-bc8d9c80f509c57810a7baabb93803620f6d88dd.tar.gz |
MFC r280262 and r280263:
Add more known bugs to the USB audio manual page.
Diffstat (limited to 'share')
-rw-r--r-- | share/man/man4/snd_uaudio.4 | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/share/man/man4/snd_uaudio.4 b/share/man/man4/snd_uaudio.4 index b045851..ccc3865 100644 --- a/share/man/man4/snd_uaudio.4 +++ b/share/man/man4/snd_uaudio.4 @@ -29,7 +29,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 24, 2011 +.Dd March 19, 2015 .Dt SND_UAUDIO 4 .Os .Sh NAME @@ -91,12 +91,27 @@ by The .Tn PCM framework in -.Fx , -as of this writing, does not handle device un-registrations in a properly -abstracted manner, i.e., a detach request is refused by the -.Tn PCM -framework if the device is in use. -It is necessary to allow the device un-registration to complete -successfully, otherwise the +.Fx +only supports synchronous device detach. +That means all mixer and DSP character devices belonging to a given +USB audio device must be closed when receiving an error on a DSP read, +a DSP write or a DSP IOCTL request. +Else the USB audio driver will wait for this to happen, preventing +enumeration of new devices on the parenting USB controller. +.Pp +Some USB audio devices might refuse to work properly unless the sample +rate is configured the same for both recording and playback, even if +only simplex is used. +See the +.Va dev.pcm.%d.[play|rec].vchanrate +sysctls. +.Pp +The .Tn PCM -layer will panic. +framework in +.Fx +currently doesn't support the full set of USB audio mixer +controls. +Some mixer controls are only available as +.Va dev.pcm.%d.mixer +sysctls. |