Under what circumstances is there ACPI.sys in the disk stack?

NTDEV
1

Hi,

I do a disk stack analysis quite often. Most often the stack looks like this:
[i-dont-care] -> partmgr.sys ->disk.sys -> [miniport driver (atapi, iastor, lsi_scsi)].

Sometimes, there is ACPI.sys below the disk class driver:
[i-dont-care] -> partmgr.sys ->disk.sys -> ACPI.sys -> [miniport driver].

What kind of hardware/software configuration causes this?

L.

2

> Sometimes, there is ACPI.sys below the disk class driver:

[i-dont-care] -> partmgr.sys ->disk.sys -> ACPI.sys -> [miniport driver].

IIRC the MSDN docs on ACPI.sys describe the fact that there are “ACPI-driven” devices, which only exist as an ACPI table record and cannot be enumerated any other way (like power button or lid), and there are “ACPI-aware” devices, which are enumerated the other way (on SATA bus, for instance), but still have ACPI table entries.

IDE/SATA disks are a good sample. They are enumerated using INQUIRY/IDENTIFY, but have ACPI table records for them. More so, in good old times of Pentium III and w2k, the ACPI table entries for them were editable by BIOS setup screens and contained the DMA mode for a disk. Then the booted OS was mandated to use this DMA mode.

ACPI.sys is installed as a filter for such devices.

–
Maxim S. Shatskih
Microsoft MVP on File System And Storage
xxxxx@storagecraft.com
http://www.storagecraft.com

3

Thanks Maxim!

Ladik