Re: Loading DSDT table using 'acpi' or some memory write command?

[Vladimir 'phcoder' Serbinenko]

On Mon, Feb 27, 2017, 07:13 Vladimir 'phcoder' Serbinenko <address@hidden> wrote:

I reproduced the bug. I'm investigating

Apparently finish_boot_services rewrites acpi tables. It's possible to workaround this, possibly by using acpi table protocol. But it's certainely not for 2.02 at this point.

On Mon, Feb 27, 2017, 05:53 Andrei Borzenkov <address@hidden> wrote:

On Mon, Feb 27, 2017 at 2:29 PM, Nando Eva <address@hidden> wrote:
> @Andrei Borzenkov, I've confirmed that any of the following do not alter the
> Win10 DSDT table across numerous Macbooks and my Dell E6540.
>
> acpi dsdt.aml
> acpi --load-only dsdt dsdt.aml
> acpi -2 dsdt.aml
>
> Followed by:
> chainloader /efi/Microsoft/Boot/bootmgfw.efi
>
> Clover has a DSDT override function and using it works on my Dell E6540.
> However it does it by writing to the UEFI firmware volume, which for
> Macbooks, has had one test instance of bricking the system.
>
> Any chance of a simple  'load_dsdt [file]' command that acquires the
> in-memory DSDT table address, checks it's size, then overwrites it with the
> file name specified if it's the same size or smaller?
>

That's more or less what grub tries to do. We cannot really overwrite
ACPI tables because they may be located in read-only memory, but it
attempts to create EBDA and place new RSDP there and update EBDA
address as well as update RSDP pointer in EFI system table. I would
suggest trying to load something else (like Linux) and check whether
it sees new or old table.

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