1. 01 5月, 2007 2 次提交
    • L
      ACPI: delete un-reliable concept of cooling mode · eaca2d3f
      Len Brown 提交于
      The scheme where the thermal driver displayed the
      cooling mode /proc/acpi/thermal_zone/*/cooling_mode
      was flawed in two ways.
      
      First, the success of _SCP doesn't actually mean
      that the BIOS moved any trip points.
      On many BIOS, _SCP is present, but does nothing.
      So displaying what _SCP executed actually
      was wrong more times than it was right.
      
      Second, examining the relative position of the
      trip points when the thermal_zone is added
      is insufficient -- as the BIOS reserves the right
      to change the trip points at run-time.
      
      The only reliable way for the user to determine if
      the thermal zone is in active, passive, or critical
      mode is to examine the relative position of the trip points.
      The user can do this without the kernel doing it
      for them by looking in /proc/acpi/thermal_zone/*/trip_points
      
      New contents for /proc/acpi/thermal_zone/*/cooling_mode:
      
      If _SCP available:
      "0 - Active; 1 - Passive\n"
      
      If _SCP unavailable:
      "<setting not supported>\n"
      Signed-off-by: NLen Brown <len.brown@intel.com>
      eaca2d3f
    • L
      ACPI: thermal trip points are read-only · 11ccc0f2
      Len Brown 提交于
      /proc/acpi/thermal_zone/*/trip_points displays
      what the kernel reads from the BIOS via ACPI.
      
      If you echo a string of ':' deliminted numbers to this file
      then it will change what it displays.
      
      But it shouldn't, since the kernel has no way to communicate
      these changes to ACPI thermal zones.  ACPI thermal zone
      trip points are read-only.
      
      The kernel does have the opportunity to ask the BIOS to change
      the trip points with _SCP - Set Cooling Policy.
      
      Request Active Cooling Mode:
      # echo 0 > /proc/acpi/thermal_zone/*/cooling_policy
      
      Request Passive Cooling Mode:
      # echo 1 > /proc/acpi/thermal_zone/*/cooling_policy
      
      However, in practice it is quite rare for the BIOS
      to support the optional _SCP, and it is even more rare
      for the BIOS to export an _SCP that actually changes
      the trip points.
      Signed-off-by: NLen Brown <len.brown@intel.com>
      11ccc0f2
  2. 26 4月, 2007 5 次提交
  3. 25 4月, 2007 13 次提交
  4. 24 4月, 2007 20 次提交