[syslinux] State of memdisk-acpi

Sebastian Herbszt herbszt at gmx.de
Wed Nov 7 13:58:20 PST 2012

Shao Miller wrote:
> On 11/7/2012 14:46, Sebastian Herbszt wrote:
>> Unfortunately it's unclear to me what we gain by hooking the DSDT/SSDT.
>> How can we access the mBFT?
> Well under Windows, the ACPI pieces are enumerated as device nodes in 
> the PnP device tree.  Each node has a device ID provided by whoever 
> populated the ACPI pieces.  Windows then checks a couple of different 
> areas to find out how to drive the "device."
> hpa obtained an ACPI vendor ID from Microsoft.
> Ideally, a MEMDISK could be enumerated as a device using this strategy, 
> then a driver like WinVBlock could be registered to drive devices with 
> those IDs.  Currently, WinVBlock has create its own device, rather than 
> more simply being requested to drive a device that was enumerated by the 
> ACPI driver.

Seems i misinterpreted the goal of memdisk-acpi.

> In either case, the mBFT is accessed by reading memory.  With an ACPI 
> table, I believe the mBFT position is known.  Without, it needs to be 
> scanned-for, just like the iBFT and aBFT of iSCSI and AoE, respectively.

I hoped memdisk-acpi would allow me to get memdisk parameters on windows
from user space with GetSystemFirmwareTable.

> I don't know if Linux has a similar ACPI device enumeration strategy.

Linux provides 'acpi:HPA0001' as modalias.


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