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#1 2022-04-29 07:55:16

Registered: 2022-04-29
Posts: 1

USB Microphone stops working after a few seconds idle

I have a USB mic that reports as "31b2:0011 DCMT Technology USB Condenser Microphone" with a weird issue: after first plugging it in, it records just fine, but after a few seconds of no use, it no longer produces any output.

The following command line illustrates and perfectly reproduces the issue:

 parec | pv > /dev/null ; sleep 5 ; parec | pv > /dev/null 

I run this command and unplug/re-plug the microphone; the output from the first parec -> pv pipe shows a constant 172KiB/s. Then I type Ctrl-C to interrupt the first parec process; the one after the sleep outputs 0KiB/s; if I then re-plug the device again it goes back to 172KiB/s. If I reduce the sleep time to 4 seconds or shorter, the second parec process outpus 172KiB/s immediately without needing to re-plug, so whatever issue this is seems to occur after 4-5 seconds of no recording.

The only relevant messages in the journal / dmesg appear when un-/plugging the cable, and look pretty benign, e.g.:

usb 2-1.8.4: USB disconnect, device number 14
usb 2-1.8.4: new full-speed USB device number 15 using ehci-pci
usb 2-1.8.4: config 1 has an invalid interface number: 3 but max is 2
usb 2-1.8.4: config 1 has no interface number 2
usb 2-1.8.4: New USB device found, idVendor=31b2, idProduct=0011, bcdDevice= 1.00
usb 2-1.8.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1.8.4: Product: USB Condenser Microphone
usb 2-1.8.4: Manufacturer: DCMT Technology
usb 2-1.8.4: SerialNumber: 214b206000000178
input: DCMT Technology USB Condenser Microphone as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.8/2-1.8.4/2-1.8.4:1.3/0003:31B2:0011.0010/input/input42
hid-generic 0003:31B2:0011.0010: input,hidraw4: USB HID v1.10 Device [DCMT Technology USB Condenser Microphone] on usb-0000:00:1d.0-1.8.4/input3

Could the "interface number" messages be a clue?

As long as I keep a

parec > /dev/null

running constantly (doesn't interfere with other programs recording), I can use the microphone without issue for days on end, so this is not a serious problem. Still, any ideas for how I could further debug this are appreciated.

Edited to add: this issue has persisted through the last few full system upgrades

Last edited by mvoelske (2022-04-29 07:57:08)


#2 2022-04-29 12:26:11

Forum Moderator
Registered: 2012-10-16
Posts: 16,497

Re: USB Microphone stops working after a few seconds idle

usb autosuspend kicking in too hard for the mic? … utosuspend You could also disable/unload pulses module-suspend-on-idle but this will just have the logically same implication as your /dev/null parec.

Last edited by V1del (2022-04-29 12:27:26)


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