[syslinux] State of memdisk-acpi

[Shao Miller]

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.

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

- Shao Miller