ACPI: Add facility to remove all _OSI strings
This patch changes the "acpi_osi=" boot parameter implementation so
that:
1. "acpi_osi=!" can be used to disable all _OSI OS vendor strings by
default. It is meaningless to specify "acpi_osi=!" multiple
times as it can only affect the default state of the target _OSI
strings.
2. "acpi_osi=!*" can be used to remove all _OSI OS vendor strings
and all _OSI feature group strings. It is useful to specify
"acpi_osi=!*" multiple times through kernel command line to
override the current state of the target _OSI strings.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d0d9cf2..5ec77aa 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -237,6 +237,7 @@
acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
acpi_osi="string1" # add string1
acpi_osi="!string2" # remove string2
+ acpi_osi=!* # remove all strings
acpi_osi=! # disable all built-in OS vendor
strings
acpi_osi= # disable all strings
@@ -248,7 +249,9 @@
it cannot affect the default state of the feature group
strings and the current state of the OS vendor strings,
specifying it multiple times through kernel command line
- is meaningless.
+ is meaningless. This command is useful when one do not
+ care about the state of the feature group strings which
+ should be controlled by the OSPM.
Examples:
1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
to 'acpi_osi="Windows 2000" acpi_osi=!', they all
@@ -264,6 +267,29 @@
1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
FALSE.
+ 'acpi_osi=!*' can be used in combination with single or
+ multiple 'acpi_osi="string1"' to support specific
+ string(s). Note that such command can affect the
+ current state of both the OS vendor strings and the
+ feature group strings, thus specifying it multiple times
+ through kernel command line is meaningful. But it may
+ still not able to affect the final state of a string if
+ there are quirks related to this string. This command
+ is useful when one want to control the state of the
+ feature group strings to debug BIOS issues related to
+ the OSPM features.
+ Examples:
+ 1. 'acpi_osi="Module Device" acpi_osi=!*' can make
+ '_OSI("Module Device")' FALSE.
+ 2. 'acpi_osi=!* acpi_osi="Module Device"' can make
+ '_OSI("Module Device")' TRUE.
+ 3. 'acpi_osi=! acpi_osi=!* acpi_osi="Windows 2000"' is
+ equivalent to
+ 'acpi_osi=!* acpi_osi=! acpi_osi="Windows 2000"'
+ and
+ 'acpi_osi=!* acpi_osi="Windows 2000" acpi_osi=!',
+ they all will make '_OSI("Windows 2000")' TRUE.
+
acpi_pm_good [X86]
Override the pmtimer bug detection: force the kernel
to assume that this machine's pmtimer latches its value