Rubin Shrestha
Rubin Shrestha
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Force ICH7-M in AHCI mode, with grub2 plus setpci, works in Linux, but what about Windows?

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this is my first post, forgive me if I am in the wrong place or if my post is considered inappropriate.
I have borrowed the idea from numerous Mac user forums, after I added a SSD disk to my Sony VAIO VPCW12J1E, 32bit, dual booting Debian Sid / Windows 7 Starter on standard MBR – no GPT, no EFI, no UEFI.
The netbook is equipped with a heavily mutilated Phoenix BIOS, which lacks the option to set the chipset in AHCI mode (see my post here for example).
With Debian already installed in IDE mode, and initramfs-tools package, it’s all quite simple:

  1. nano /etc/initramfs-tools/modules – at the end of the file, add a first line to load the module ahci and a second line for the module libahci ;
  2. nano /etc/initramfs-tools/conf.d/driver-policy – change from MODULES=dep to MODULES=list ;
  3. then regenerate yours initrd images – update-initramfs -u -k all and lsinitramfs /boot/initrd.img-'uname -r' | grep -i ahci just to be sure that the needed modules are in place;
  4. nano /etc/grub.d/40_custom – write a custom menuentry and, immediately after the last line initrd /initrd.img just write setpci -s 0:1f.2 90.b=40 and then close the stanza with the } symbol;
  5. then update-grub ;
  6. and lastly again update-initramfs -u -k all .

Reboot, choose your custom menuentry, enjoy Debian with SSD in AHCI mode (see attachment #1 on my Google Drive).

With Windows is another story, the previous magic string does not suffice alone and indeed, it prevents the system from seeing the SSD disk – so it does not boot.
But I believe the SATA settings mentioned in the official datasheet can be translated into other setpci strings, tailored to a standard PC (as are specifically dedicated the strings and the other solutions spreaded on the WWW and already applied to Macs, I have already tried them on my netbook but to no avail).
I can provide whole PCI configuration space of my ICH7-M in IDE and AHCI mode to get a diff (see attachment #2) but I would need a lot of help translating the differences into the right strings (I think I need to set at least the SCRAE bit plus enable some ABARs on irq 24 and so on, in the end passing the strings in the right sequence from grub2).
Please, anyone can help me?

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