RE: [Devel] [PATCH 1/4] ACPI: Provide support for ACPI table adding via OS

Zheng, Lv
2014-02-21T07:28:08Z

Hi, Thomas

> From: Devel [mailto:devel-bounces@acpica.org] On Behalf Of Thomas Renninger
> Sent: Wednesday, February 19, 2014 2:44 AM
>
> On Tuesday, February 18, 2014 10:27:23 AM H. Peter Anvin wrote:
> > Why can't you add SSDTs? It would be particularly useful.
>
> There are 2 ways how ACPI tables get added:
> - Via pointer from a root table (XSDT or RSDT iirc)
> - Via load statement inside of ACPI context when ACPI BIOS
> code gets executed (iirc the physical address is passed).
>
> The latter is only for SSDTs.
> The problem is that you if you add an SSDT early, it might
> have been intended for overriding when an SSDT gets dynamically
> loaded later when the system is up which is particular useful as
> well if you want to debug this specific BIOS table.
>
> This could be workarounded via a boot param:
> acpi=allow_ssdt_adding
> But this is not nice. Maybe someone has a more elegant idea.
> Something could still be added if someone is really needing this.

I'm not sure if you are talking about the issue that:
If a system booted using customized DSDT embedded with SSDT, it also requires dynamic SSDT loading be prevented in ACPICA.

Thanks and best regards
-Lv

>
> Thomas
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