Date: Thu, 19 Mar 2015 15:32:56 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r280262 - head/share/man/man4 Message-ID: <201503191532.t2JFWuUH009390@svn.freebsd.org>
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Author: hselasky Date: Thu Mar 19 15:32:55 2015 New Revision: 280262 URL: https://svnweb.freebsd.org/changeset/base/280262 Log: Add more known bugs to the USB audio manual page. MFC after: 1 week Modified: head/share/man/man4/snd_uaudio.4 Modified: head/share/man/man4/snd_uaudio.4 ============================================================================== --- head/share/man/man4/snd_uaudio.4 Thu Mar 19 14:09:27 2015 (r280261) +++ head/share/man/man4/snd_uaudio.4 Thu Mar 19 15:32:55 2015 (r280262) @@ -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.
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