[ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface

[mv-sheeva.git] / Documentation / cpu-freq / user-guide.txt

diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt
index 2a5b850847c024e676395320f534c1982c8ae33a..04f6b32993e69ca4185a81bbaadb677aac5056e9 100644 (file)
--- a/Documentation/cpu-freq/user-guide.txt
+++ b/Documentation/cpu-freq/user-guide.txt
@@ -203,6 +203,17 @@ scaling_cur_freq :         Current frequency of the CPU as determined by
                                the frequency the kernel thinks the CPU runs
                                at.
 
+bios_limit :                   If the BIOS tells the OS to limit a CPU to
+                               lower frequencies, the user can read out the
+                               maximum available frequency from this file.
+                               This typically can happen through (often not
+                               intended) BIOS settings, restrictions
+                               triggered through a service processor or other
+                               BIOS/HW based implementations.
+                               This does not cover thermal ACPI limitations
+                               which can be detected through the generic
+                               thermal driver.
+
 If you have selected the "userspace" governor which allows you to
 set the CPU operating frequency to a specific value, you can read out
 the current frequency in