Boot regression in 4.8 for Mac Pro server

[Scott Talbert <swt@xxxxxxxxxx>]

Hi,

I just recently discovered a boot regression that occurred starting in 4.8 
on a Mac Pro Mid-2012 server (MacPro5,1).  Yes, I realize this problem is 
over 3 years old.  Obviously, I haven't been using Linux on this hardware 
in a while.  :-)  I bisected the regression to 
475fb4e8b2f4444d1d7b406ff3a7d21bc89a1e6f "efi / ACPI: load SSTDs from EFI 
variables".  And indeed, v5.3-rc7 will boot if I comment out the 
efivar_ssdt_load() call, as in:

$ git diff
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index ad3b1f4866b3..691a8671a2ba 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -364,8 +364,8 @@ static int __init efisubsys_init(void)
        if (error)
                goto err_put;

-       if (efi_enabled(EFI_RUNTIME_SERVICES))
-               efivar_ssdt_load();
+       //if (efi_enabled(EFI_RUNTIME_SERVICES))
+       //      efivar_ssdt_load();

        error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
        if (error) {


Any thoughts on how to fix this?

Thanks,
Scott