[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.
Sebastian
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