Virtual PCM Test Driver Coming With Linux 6.5 To Help With Audio Testing & Fuzzing

Written by Michael Larabel in Multimedia on 13 June 2023 at 06:09 AM EDT. Add A Comment
Last month I wrote about the virtual ALSA driver being developed for the Linux kernel. That driver has now morphed into the Virtual PCM Test driver and is on its way with the upcoming Linux 6.5 cycle.

The "pcmtest" Virtual PCM Test driver emulates a generic PCM device and can be used for testing/fuzzing of user-space ALSA applications as well as stressing Linux's PCM middle layer. The hope is this driver can also be used for simulating hard-to-reproduce problems with PCM devices.

This virtual audio driver can simulate both the capture and playback processes, generate random or pattern-based capturing data, inject delays into playback/capturing processes, and/or inject errors during the PCM callbacks. This new driver should be helpful for Linux kernel sound subsystem developers and ALSA user-space software developers in fuzzing, bug fixing, and all-around making Linux audio better.

pcmtest Kconfig

This new driver has been queued into the sound.git's for-next branch by maintainer Takashi Iwai ahead of the upcoming Linux 6.5 merge window.

Also exciting on the sound front with Linux 6.5 is MIDI 2.0 driver support.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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