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author | hselasky <hselasky@FreeBSD.org> | 2015-03-19 15:32:55 +0000 |
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committer | hselasky <hselasky@FreeBSD.org> | 2015-03-19 15:32:55 +0000 |
commit | 91d98cc1fb473e9f1cfa921d5eae75d7eece375e (patch) | |
tree | 83a0c2bf2353c163db61c8462b89145046e3056a /share/man/man4/snd_uaudio.4 | |
parent | b178649de896674ad1d1de14d554fa49b29ec19b (diff) | |
download | FreeBSD-src-91d98cc1fb473e9f1cfa921d5eae75d7eece375e.zip FreeBSD-src-91d98cc1fb473e9f1cfa921d5eae75d7eece375e.tar.gz |
Add more known bugs to the USB audio manual page.
MFC after: 1 week
Diffstat (limited to 'share/man/man4/snd_uaudio.4')
-rw-r--r-- | share/man/man4/snd_uaudio.4 | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/share/man/man4/snd_uaudio.4 b/share/man/man4/snd_uaudio.4 index d104947..91b0c99 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 +91,25 @@ 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. |