From 048c2f2ac0d7712b74928cbdbba16f51c69f8c6d Mon Sep 17 00:00:00 2001 From: Felix Held Date: Mon, 21 Aug 2023 19:02:52 +0200 Subject: Documentation/acpi: add Windows-specific documentation When using the Windows fast startup mechanism which is enabled by default, Windows will use a cached version of the ACPI tables during normal boots after a clean shutdown. Since I've run into this issue and spent quite a bit of time debugging the wrong issue due to this, better document this possibly unexpected behavior. Signed-off-by: Felix Held Change-Id: Ia9e65f6a3aff13fa54abe68c8f5fcbf9bc6efc1a Reviewed-on: https://review.coreboot.org/c/coreboot/+/77354 Tested-by: build bot (Jenkins) Reviewed-by: Nico Huber Reviewed-by: Paul Menzel Reviewed-by: Matt DeVillier --- Documentation/acpi/index.md | 3 +++ Documentation/acpi/windows.md | 9 +++++++++ 2 files changed, 12 insertions(+) create mode 100644 Documentation/acpi/windows.md (limited to 'Documentation/acpi') diff --git a/Documentation/acpi/index.md b/Documentation/acpi/index.md index 0009837fcbcb..f9ae42576026 100644 --- a/Documentation/acpi/index.md +++ b/Documentation/acpi/index.md @@ -11,6 +11,9 @@ upwards. - [GPIO toggling in ACPI AML](gpio.md) +## Windows-specific ACPI documentation + +- [Windows-specific documentation](windows.md) ## ACPI specification - Useful links diff --git a/Documentation/acpi/windows.md b/Documentation/acpi/windows.md new file mode 100644 index 000000000000..5745df8e8a64 --- /dev/null +++ b/Documentation/acpi/windows.md @@ -0,0 +1,9 @@ +# Testing ACPI changes under Windows + +When testing ACPI changes in coreboot against Windows 8 or newer, beware that +during a normal boot after a clean shutdown, Windows will use the fast startup +mechanism which results in it not evaluating the changed ACPI code but instead +using some cached version which won't include the changes that were supposed to +be tested. In order for Windows to actually use the new ACPI tables, either +disable the fast startup or just tell Windows to do a reboot which will make it +read and use the ACPI tables in memory instead of an outdated cached version. -- cgit v1.2.3