Archive for December, 2017

USB Driver Stack: improvements for the USB Audio driver

The legacy usb driver stack version 10.x branch is constantly being update by Lars Erdmann and Wim Brul. In 2017 the USB Audio driver got a lot of fixes and new functionality. One part of the patches is for the stream handling that fixes problems after a stream resume in case another stream was played. Starting with driver version 10.217 the usbaudio driver comes with an additional wps ioproc module called “usbwave” which does the on fly sample rate conversion, this is required because the usb audio hardware often supports a fixed sample rate only.

The ioproc need to be installed separately from the USB Audio driver:

usbaudio wave ioproc installation

usbaudio wave ioproc installation

In case it is correctly installed it should be listed in the WPS Multimedia Codes page:

usbaudio wave ioproc mmcodecs

usbaudio wave ioproc mmcodecs

Audio applications which are using the pmmm interface will work in this setup but audio application/mixer that may talk directly to the audio driver, e.g. uniaud or use the ioclt90 interface will not work.


Team OS/4: OS/4 kernel support for AMD Ryzen CPU

The OS/4 Kernel Team recently updated the OS/4 kernel to support the AMD Ryzen CPU, which has the famous VME bug found by Michal from the os2museum. AMD fixed the issue with a microcode update found in the AGESA BIOS blob.


  • updated oemhlp kernel driver which contains a patch for the AMD Ryzen VME bug
  • kernel support for the AVX CPU instructions found in recent AMD and Intel CPUs
  • new pmdd.sys/pmddk.sys which talks to the new KEE interface but it is also compatible with the IBM Aurora CP SMP Kernel