to U-Boot. This should go at the top of each file and list the coreboot
filename where the code originated.
+Debugging ACPI issues with Windows:
+
+Windows might cache system information and only detect ACPI changes if you
+modify the ACPI table versions. So tweak them liberally when debugging ACPI
+issues with Windows.
+
ACPI Support Status
-------------------
Advanced Configuration and Power Interface (ACPI) [16] aims to establish
* Support one static DSDT table only, compiled by Intel ACPI compiler.
* Support S0/S5, reboot and shutdown from OS.
* Support booting a pre-installed Ubuntu distribution via 'zboot' command.
+ * Support installing and booting Ubuntu 14.04 (or above) from U-Boot with
+ the help of SeaBIOS using legacy interface (non-UEFI mode).
+ * Support installing and booting Windows 8.1/10 from U-Boot with the help
+ of SeaBIOS using legacy interface (non-UEFI mode).
* Support ACPI interrupts with SCI only.
Features not supported so far (to make it a complete ACPI solution):
* S3 (Suspend to RAM), S4 (Suspend to Disk).
- * Install and boot Ubuntu 14.04 (or above) from U-Boot with legacy interface.
- * Install and boot Windows 8.1/10 from U-Boot with legacy interface.
Features that are optional:
- * ACPI global NVS support. We may need it to simplify ASL code logic if
- utilizing NVS variables. Most likely we will need this sooner or later.
* Dynamic AML bytecodes insertion at run-time. We may need this to support
SSDT table generation and DSDT fix up.
* SMI support. Since U-Boot is a modern bootloader, we don't want to bring
those legacy stuff into U-Boot. ACPI spec allows a system that does not
support SMI (a legacy-free system).
-So far ACPI is enabled on BayTrail based boards. Testing was done by booting
-a pre-installed Ubuntu 14.04 from a SATA drive. Most devices seem to work
-correctly and the board can respond a reboot/shutdown command from Ubuntu.
+ACPI was initially enabled on BayTrail based boards. Testing was done by booting
+a pre-installed Ubuntu 14.04 from a SATA drive. Installing Ubuntu 14.04 and
+Windows 8.1/10 to a SATA drive and booting from there is also tested. Most
+devices seem to work correctly and the board can respond a reboot/shutdown
+command from the OS.
+
+For other platform boards, ACPI support status can be checked by examining their
+board defconfig files to see if CONFIG_GENERATE_ACPI_TABLE is set to y.
TODO List
---------