Hi I'm using a pair of KEF X300A speakers, which get recognized by the uaudio driver. Sporadically get: uaudio0: at uhub4, port 2, addr 3 (disconnected) pcm0: unregister: channel pcm0:virtual:dsp0.vp0 busy (pid 2204) pcm0: Waiting for sound application to exit! pcm0: unregister: channel pcm0:virtual:dsp0.vp0 busy (pid 2204) pcm0: Waiting for sound application to exit! pcm0: unregister: channel pcm0:virtual:dsp0.vp0 busy (pid 2204) pcm0: Waiting for sound application to exit! [... -- closing/killing the concerning the application] pcm0: Waiting for sound application to exit! pcm0: unregister: mixer busy pcm0: Waiting for sound application to exit! pcm0: unregister: mixer busy [repeat at infinitum] The usb-stack seems to be completly hung at this point (usbconfig&friends hang) -- until I close everything else that has /dev/mixer* open. Then the device seems to reattach and gets usable again.
Hi, This is correct behaviour from the kernel. We need to trace down these apps and make them disconnect the mixer device when the USB AUDIO device detaches. Possibly same with pulseaudio. Do you know which mixer APP this is? XFCE? --HPS
Hi 2204 was mplayer. The one I had to kill to get the stack unhung was kdeinit. So I guess it is a problem in kde. mfg Tobias
Is this expected behaviour when entering sleep, however? Apps have stopped but not freed the pcm device. Looks like i'll be running fuser before acpiconf. ;) Would it make more sense to _eventually_ give up and and send EPIPE or similar? \
Hi, Yes, mixer apps must close their handles when they detect the device is gone! --HPS
This is illogical. USB supports hot plug, so kernel must handle it without stucking. I use audio with KVM b/w Linux. Windows and FreeBSD and I can't even kill mixer as entire USB waits indefinitely. My observations with FF playing youtube video 1. Windows - active playback resumes after FF restart 2. Linux - active playback resumes after FF restart 3. FreeBSD needs reset button.
Hi, Applications must close their handles upon detecting failures, like detach. Else device numbers will be used up pretty quickly. This is a known issue. One solution is perhaps to use audio/virtual_oss, which proxy access to /dev/dsp and possibly in the future /dev/mixer aswell, so that these FreeBSD specific artifacts are hidden. --HPS
Interesting solution indeed! However, looks like I'm out of luck as several processes attached to mixer. abishai@darkstar:~ % fstat /dev/dsp* /dev/mixer* USER CMD PID FD MOUNT INUM MODE SZ|DV R/W NAME abishai kmix 3325 13 /dev 198 crw-rw-rw- mixer1 rw /dev/mixer1 abishai kmix 3325 14 /dev 198 crw-rw-rw- mixer1 rw /dev/mixer1 abishai kdeinit5 3277 2188 /dev 198 crw-rw-rw- mixer1 rw /dev/mixer1 abishai kdeinit5 3277 2189 /dev 198 crw-rw-rw- mixer1 rw /dev/mixer1
kmix is a process in KDE5. Why not just fix it? --HPS
One solution here is that the sound driver waits a bit and then kills the process in question with SIGPIPE.
I'm not sure what will happen if kmix is killed. Will it be restarted somehow? I guess this needs a better fix.
(In reply to Hans Petter Selasky from comment #9) I think that in FreeBSD we have an ability to revoke a file descriptor. Can we use it to disassociate anything that userland has open from the device that we want to let go?
The problem is that the application, in this case a desktop application will stop working, because it will never detect that the mixer device is gone. --HPS
(In reply to Hans Petter Selasky from comment #10) I've made a simple script that kills all processes that hold descriptor, they are just quit, so I need to restart them. I don't think this is kmix only issue, users of other DE probably have another mixer. I can see that Linux has more general purpose solution Maybe, pulseaudio handles this like OSS proxy you've suggested ? Then, proxy solution is the only right, as this is seamless for userland.
Hello, I have the very same issue. I am a newbie on freebsd. I installed iFreeBSD fujitsu 11.2-RELEASE with kde5 to my fujitsu 920 minipc. I have currently no sound. Since I am trying to configure this machine as my primary desktop machine this is a show stopper for me. Is there a way to circumvent this issue.. pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: unregister: mixer busy pcm2: Waiting for sound application to exit! pcm2: detached pcm2: <USB audio> on uaudio0 pcm0: <Intel Haswell (HDMI/DP 8ch)> at nid 3 on hdaa0 pcm1: <Realtek ALC671 (Rear Analog)> at nid 33 and 24 on hdaa1 pcm2: <USB audio> on uaudio0 root@fujitsu:~ # fstat /dev/dsp* /dev/mixer* USER CMD PID FD MOUNT INUM MODE SZ|DV R/W NAME toktay pulseaudio 1117 20 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay pulseaudio 1117 30 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay pulseaudio 1117 40 /dev 97 crw-rw-rw- mixer2 rw /dev/mixer2 toktay kmix 1113 13 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay kmix 1113 14 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay kmix 1113 15 /dev 97 crw-rw-rw- mixer2 rw /dev/mixer2 toktay kdeinit5 1049 2564 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay kdeinit5 1049 2608 /dev 62 crw-rw-rw- mixer1 rw /dev/mixer1 toktay kdeinit5 1049 2610 /dev 97 crw-rw-rw- mixer2 rw /dev/mixer2
(In reply to Hans Petter Selasky from comment #1) Many applications fail to disconnect from mixer when required. How is it "correct behaviour from the kernel" for the kernel to only behave correctly (keep USB and suspend working) when applications also behave correctly? These audio playback applications are not normally granted permission to obstruct kernel facilities. The virtual_oss behaves very well indeed, but must the kernel remain so fragile that virtual_oss is the only application I should grant permission to access /dev/dsp ? (In reply to Hans Petter Selasky from comment #9) "One solution here is that the sound driver waits a bit and then kills the process in question with SIGPIPE." This is much more acceptable than putting the system into an unrecoverable state when attempting to sleep (compare the established behavior of killing any processes which refuse to quit during full shutdown).
I've had the same issue since FreeBSD 11.2-RELEASE with if_uaudio.ko and audio/cmus. Audio device is a 9 year old HRT MusicStreamer II+. When I was on FreeBSD 11.2, the system would suspend, but USB hung up when resumed. In FreeBSD 12.0-RELEASE, the stalled usb drivers will stall before suspending has finished. I tried to disconnecting the audio device when USB stalls, but that doesn't help Only solution is to ssh into the machine and kill cmus (no -9 needed) and usb keyboard and mouse, etc will come back to life and suspend/resume will finish. /dev/ttyv0 is flooded with "Waiting for mixer..." and "Waiting for sound application to exit" This is on USB 2.0 native on Intel Broadwell CPU. I already posted that on the forums in november 2018: https://forums.freebsd.org/threads/weird-xhci-crash-freeze-after-resume-from-suspend.68277/ I wonder if this is specific to a Intel processor/chipset generation, as almost every new generation of Intel processors/chipsets comes with a new set of bugs. Though that's just a guess. I have another computer with a different audio device using if_uaudio.ko, a Asus Impressario BluRayDrive with Xonar audio. This one works fine with suspend/resume on FreeBSD 12.0-RELEASE. I'll move the audio-devices around and post back, maybe that'll give a hint what's the cause. -Matthias