diff options
| -rw-r--r-- | Documentation/firmware-guide/acpi/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/firmware-guide/acpi/osi.rst (renamed from Documentation/acpi/osi.txt) | 15 |
2 files changed, 10 insertions, 6 deletions
diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst index 99677c73f1fb..868bd25a3398 100644 --- a/Documentation/firmware-guide/acpi/index.rst +++ b/Documentation/firmware-guide/acpi/index.rst @@ -9,3 +9,4 @@ ACPI Support namespace enumeration + osi diff --git a/Documentation/acpi/osi.txt b/Documentation/firmware-guide/acpi/osi.rst index 50cde0ceb9b0..29e9ef79ebc0 100644 --- a/Documentation/acpi/osi.txt +++ b/Documentation/firmware-guide/acpi/osi.rst @@ -1,5 +1,8 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================== ACPI _OSI and _REV methods --------------------------- +========================== An ACPI BIOS can use the "Operating System Interfaces" method (_OSI) to find out what the operating system supports. Eg. If BIOS @@ -14,7 +17,7 @@ This document explains how and why the BIOS and Linux should use these methods. It also explains how and why they are widely misused. How to use _OSI ---------------- +=============== Linux runs on two groups of machines -- those that are tested by the OEM to be compatible with Linux, and those that were never tested with Linux, @@ -62,7 +65,7 @@ the string when that support is added to the kernel. That was easy. Read on, to find out how to do it wrong. Before _OSI, there was _OS --------------------------- +========================== ACPI 1.0 specified "_OS" as an "object that evaluates to a string that identifies the operating system." @@ -96,7 +99,7 @@ That is the *only* viable strategy, as that is what modern Windows does, and so doing otherwise could steer the BIOS down an untested path. _OSI is born, and immediately misused --------------------------------------- +===================================== With _OSI, the *BIOS* provides the string describing an interface, and asks the OS: "YES/NO, are you compatible with this interface?" @@ -144,7 +147,7 @@ catastrophic failure resulting from the BIOS taking paths that were never validated under *any* OS. Do not use _REV ---------------- +=============== Since _OSI("Linux") went away, some BIOS writers used _REV to support Linux and Windows differences in the same BIOS. @@ -164,7 +167,7 @@ from mid-2015 onward. The ACPI specification will also be updated to reflect that _REV is deprecated, and always returns 2. Apple Mac and _OSI("Darwin") ----------------------------- +============================ On Apple's Mac platforms, the ACPI BIOS invokes _OSI("Darwin") to determine if the machine is running Apple OSX. |