macOS ignores the root bridge constraints as too does Linux when booted with the 'pci=noCRS' parameter.

Windows OS honors the root bridge definition and will allocate PCIe devices within it. A watermark TOLUD value is then set and locked in the system firmware. 'A Windows system's DSDT table root bridge definition (ACPI PNP0A08 or PNP0A03) is usually confined to a reserved 32-bit space (under 4GB) budgeted to be large enough to host the notebook's PCIe devices. I had tried to pass SETPCI commands from grub into Windows 10- no luck*Ī quote from the link above got my brain spinning I had messed around with mm commands in a UEFI shell (The shell provided in the rEFIt package) to no avail*

The part that was frustrating to me was that many users like myself have lots of UEFI installs on their 2011 MBP and those OS's have no problem 'seeing' the HD audio controller. I was given the answer from a tutorial only adjacently related -here:Įssentially what we knew was that windows didn't 'see' the correct audio devices when booted in pure efi. If anyone is still interested I have found the solution for audio on MBP 2011 Windows 10 UEFI installs - it has taken me 4 years to figure out.

Apple macbook pro 2011