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Message-Id: <20190329001135.15847-10-changbin.du@gmail.com>
Date: Fri, 29 Mar 2019 08:11:20 +0800
From: Changbin Du <changbin.du@...il.com>
To: Jonathan Corbet <corbet@....net>
Cc: rjw@...ysocki.net, lenb@...nel.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
Changbin Du <changbin.du@...il.com>
Subject: [PATCH v2 09/24] acpi doc: convert acpi/method-customizing.txt to rst format
This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.
Signed-off-by: Changbin Du <changbin.du@...il.com>
---
Documentation/acpi/index.rst | 1 +
Documentation/acpi/method-customizing.rst | 82 +++++++++++++++++++++++
Documentation/acpi/method-customizing.txt | 73 --------------------
3 files changed, 83 insertions(+), 73 deletions(-)
create mode 100644 Documentation/acpi/method-customizing.rst
delete mode 100644 Documentation/acpi/method-customizing.txt
diff --git a/Documentation/acpi/index.rst b/Documentation/acpi/index.rst
index 0fae18cc1eea..409e98f19748 100644
--- a/Documentation/acpi/index.rst
+++ b/Documentation/acpi/index.rst
@@ -14,3 +14,4 @@ Linux ACPI (Advanced Configuration and Power Interface)
DSD-properties-rules
gpio-properties
scan_handlers
+ method-customizing
diff --git a/Documentation/acpi/method-customizing.rst b/Documentation/acpi/method-customizing.rst
new file mode 100644
index 000000000000..32eb1cdc1549
--- /dev/null
+++ b/Documentation/acpi/method-customizing.rst
@@ -0,0 +1,82 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Linux ACPI Custom Control Method How To
+=======================================
+
+:Author: Zhang Rui <rui.zhang@...el.com>
+
+
+Linux supports customizing ACPI control methods at runtime.
+
+Users can use this to:
+
+1. override an existing method which may not work correctly,
+ or just for debugging purposes.
+2. insert a completely new method in order to create a missing
+ method such as _OFF, _ON, _STA, _INI, etc.
+
+For these cases, it is far simpler to dynamically install a single
+control method rather than override the entire DSDT, because kernel
+rebuild/reboot is not needed and test result can be got in minutes.
+
+.. note:: Only ACPI METHOD can be overridden, any other object types like
+ "Device", "OperationRegion", are not recognized. Methods
+ declared inside scope operators are also not supported.
+.. note:: The same ACPI control method can be overridden for many times,
+ and it's always the latest one that used by Linux/kernel.
+.. note:: To get the ACPI debug object output (Store (AAAA, Debug)),
+ please run "echo 1 > /sys/module/acpi/parameters/aml_debug_output".
+
+1. override an existing method
+==============================
+a) get the ACPI table via ACPI sysfs I/F. e.g. to get the DSDT,
+ just run "cat /sys/firmware/acpi/tables/DSDT > /tmp/dsdt.dat"
+b) disassemble the table by running "iasl -d dsdt.dat".
+c) rewrite the ASL code of the method and save it in a new file,
+d) package the new file (psr.asl) to an ACPI table format.
+ Here is an example of a customized \_SB._AC._PSR method::
+
+ DefinitionBlock ("", "SSDT", 1, "", "", 0x20080715)
+ {
+ Method (\_SB_.AC._PSR, 0, NotSerialized)
+ {
+ Store ("In AC _PSR", Debug)
+ Return (ACON)
+ }
+ }
+
+ Note that the full pathname of the method in ACPI namespace
+ should be used.
+e) assemble the file to generate the AML code of the method.
+ e.g. "iasl -vw 6084 psr.asl" (psr.aml is generated as a result)
+ If parameter "-vw 6084" is not supported by your iASL compiler,
+ please try a newer version.
+f) mount debugfs by "mount -t debugfs none /sys/kernel/debug"
+g) override the old method via the debugfs by running
+ "cat /tmp/psr.aml > /sys/kernel/debug/acpi/custom_method"
+
+2. insert a new method
+======================
+This is easier than overriding an existing method.
+We just need to create the ASL code of the method we want to
+insert and then follow the step c) ~ g) in section 1.
+
+3. undo your changes
+====================
+The "undo" operation is not supported for a new inserted method
+right now, i.e. we can not remove a method currently.
+For an overridden method, in order to undo your changes, please
+save a copy of the method original ASL code in step c) section 1,
+and redo step c) ~ g) to override the method with the original one.
+
+
+.. note:: We can use a kernel with multiple custom ACPI method running,
+ But each individual write to debugfs can implement a SINGLE
+ method override. i.e. if we want to insert/override multiple
+ ACPI methods, we need to redo step c) ~ g) for multiple times.
+
+.. note:: Be aware that root can mis-use this driver to modify arbitrary
+ memory and gain additional rights, if root's privileges got
+ restricted (for example if root is not allowed to load additional
+ modules after boot).
diff --git a/Documentation/acpi/method-customizing.txt b/Documentation/acpi/method-customizing.txt
deleted file mode 100644
index 7235da975f23..000000000000
--- a/Documentation/acpi/method-customizing.txt
+++ /dev/null
@@ -1,73 +0,0 @@
-Linux ACPI Custom Control Method How To
-=======================================
-
-Written by Zhang Rui <rui.zhang@...el.com>
-
-
-Linux supports customizing ACPI control methods at runtime.
-
-Users can use this to
-1. override an existing method which may not work correctly,
- or just for debugging purposes.
-2. insert a completely new method in order to create a missing
- method such as _OFF, _ON, _STA, _INI, etc.
-For these cases, it is far simpler to dynamically install a single
-control method rather than override the entire DSDT, because kernel
-rebuild/reboot is not needed and test result can be got in minutes.
-
-Note: Only ACPI METHOD can be overridden, any other object types like
- "Device", "OperationRegion", are not recognized. Methods
- declared inside scope operators are also not supported.
-Note: The same ACPI control method can be overridden for many times,
- and it's always the latest one that used by Linux/kernel.
-Note: To get the ACPI debug object output (Store (AAAA, Debug)),
- please run "echo 1 > /sys/module/acpi/parameters/aml_debug_output".
-
-1. override an existing method
- a) get the ACPI table via ACPI sysfs I/F. e.g. to get the DSDT,
- just run "cat /sys/firmware/acpi/tables/DSDT > /tmp/dsdt.dat"
- b) disassemble the table by running "iasl -d dsdt.dat".
- c) rewrite the ASL code of the method and save it in a new file,
- d) package the new file (psr.asl) to an ACPI table format.
- Here is an example of a customized \_SB._AC._PSR method,
-
- DefinitionBlock ("", "SSDT", 1, "", "", 0x20080715)
- {
- Method (\_SB_.AC._PSR, 0, NotSerialized)
- {
- Store ("In AC _PSR", Debug)
- Return (ACON)
- }
- }
- Note that the full pathname of the method in ACPI namespace
- should be used.
- e) assemble the file to generate the AML code of the method.
- e.g. "iasl -vw 6084 psr.asl" (psr.aml is generated as a result)
- If parameter "-vw 6084" is not supported by your iASL compiler,
- please try a newer version.
- f) mount debugfs by "mount -t debugfs none /sys/kernel/debug"
- g) override the old method via the debugfs by running
- "cat /tmp/psr.aml > /sys/kernel/debug/acpi/custom_method"
-
-2. insert a new method
- This is easier than overriding an existing method.
- We just need to create the ASL code of the method we want to
- insert and then follow the step c) ~ g) in section 1.
-
-3. undo your changes
- The "undo" operation is not supported for a new inserted method
- right now, i.e. we can not remove a method currently.
- For an overridden method, in order to undo your changes, please
- save a copy of the method original ASL code in step c) section 1,
- and redo step c) ~ g) to override the method with the original one.
-
-
-Note: We can use a kernel with multiple custom ACPI method running,
- But each individual write to debugfs can implement a SINGLE
- method override. i.e. if we want to insert/override multiple
- ACPI methods, we need to redo step c) ~ g) for multiple times.
-
-Note: Be aware that root can mis-use this driver to modify arbitrary
- memory and gain additional rights, if root's privileges got
- restricted (for example if root is not allowed to load additional
- modules after boot).
--
2.20.1
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