ACPI: thermal: create "thermal.crt=C" bootparam

Some hardware will malfunction at a temperature below
the BIOS provided critical shutdown threshold.

This hook allows moving the critical trip points down
to a temperature which provokes a graceful shutdown
before the hardware malfunction.

http://bugzilla.kernel.org/show_bug.cgi?id=8884

WARNING: A trip-point override will not get noticed
until the system delivers a temperature change event,
or unless thermal zone polling is enabled.
eg. "thermal.tzp=10"

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 975f029be25c..18dcfdd29df0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1826,6 +1826,10 @@ and is between 256 and 4096 characters. It is defined in the file
                         -1: disable all active trip points in all thermal zones
                         <degrees C>: override all lowest active trip points
 
+        thermal.crt=    [HW,ACPI]
+                        -1: disable all critical trip points in all thermal zones
+                        <degrees C>: lower all critical trip points
+
         thermal.nocrt=  [HW,ACPI]
                         Set to disable actions on ACPI thermal zone
                         critical and hot trip points.