Enables audio outputs on OSX for CM6206 Audio Card. By default, although it is fully USB audio compliant, outputs are not enabled and there is no sound

Status

Fixes

• works on x64 platforms
• works with Catalina 10.15.6

Notes

Initial code:

• https://www.dr-lex.be/software/cm6206.html
• by Alexander Thomas (aka Dr. Lex)

kIOReturnExclusiveAccess case kIOReturnExclusiveAccess: sprintf(out_buf,"kIOReturnExclusiveAccess - exclusive access and device already open"); break;

Succeeded! Here they say, it doesn't matter if it happens :)

• https://tewarid.github.io/2012/04/27/access-usb-device-on-mac-os-x-using-i-o-kit.html

else if (ret == kIOReturnExclusiveAccess)
{
    // this is not a problem as we can still do some things
}

https://github.com/luisliz/CM6206-Catalina

MOZGIII / cm6206-mac-codeless-kext

• https://github.com/MOZGIII/cm6206-mac-codeless-kext
• Codeless Kext for CM6206 USB Sound Card to prevent the Apple drivers from hijacking a device
• /System/Library/Extensions/
  • became readonly
    • From within the recovery mode might be possible
  • Kexts are deprecated

Cheap Multichannel Audio on OS X

• “7.1 channel USB soundcards” based on the C-Media CM6206 chipset
• https://www.cmedia.com.tw/products

How to replace the missing optical-digital audio output on newer Macs

libusb-devel

Technical Q&A QA1370 - Common QA and Roadmap for USB Software Development on Mac OS X

Technical Q&A QA1075 - Making sense of IOKit error codes

USBInterfaceOpen

USBInterfaceOpen fails always

USBInterfaceOpen always report kIOReturnExclusiveAccess error

kernel extensions (KEXTs)

Apple deprecating macOS kernel extensions (KEXTs) is a great win for security

How to delete kexts in Catalina?

“Read-only file system” when I try to touch in Mac OS Catalina

• Apple kernel extension APIs to be deprecated in macOS 10.15.4.

How to Add and Remove Kexts from macOS

• https://www.tonymacx86.com/resources/kextbeast-2-0-2.399/

MultiBeast 12.3.0 - Catalina 12.3.0

• MultiBeast, the ultimate post-installation utility, has been updated to version 12.3.0 for macOS Catalina 10.15.5+.

USB Audio

https://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg25003.html https://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg25017.html Linux Kernel & Device Driver Programming