commit 994971af45dc06d0064e1b1bfd1d3c27989f107d
author Michael Niewöhner <foss@mniewoehner.de> Sun Dec 20 15:44:13 2020 +0100
committer Nico Huber <nico.h@gmx.de> Mon Dec 21 17:40:35 2020 +0000
tree bc9704d04299c7307e7c929c62d16dcda18ee181
parent dde0630af418e6a3c2cd391579df5cea7350095a

gma: actually enable/disable backlight with new backlight control

In order to enable or disable the backlight on platforms with the new
backlight control, both enable bits in the PWM register and the
PP_CONTROL register need to bet set. Currently, the code only sets one
or the other.

Also, reverse the order in the disable case so that PWM gets disabled
after the backlight enable bit in PP_CONTROL.

Tested successfully on Clevo L141CU (CML).

Change-Id: Ib3827e744e86a9d29e09da3c5fd44d226f0b41b5
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/libgfxinit/+/48770
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

common/hw-gfx-gma-panel.adb

diff --git a/common/hw-gfx-gma-panel.adb b/common/hw-gfx-gma-panel.adb
index e343deb..532bf67 100644
--- a/common/hw-gfx-gma-panel.adb
+++ b/common/hw-gfx-gma-panel.adb
@@ -428,11 +428,11 @@
          Registers.Set_Mask
            (Register => BLC (Panel).CTL,
             Mask     => BXT_BLC_PWM_CTL_ENABLE);
-      else
-         Registers.Set_Mask
-           (Register => PP (Panel).CONTROL,
-            Mask     => PCH_PP_CONTROL_BACKLIGHT_ENABLE);
       end if;
+
+      Registers.Set_Mask
+        (Register => PP (Panel).CONTROL,
+         Mask     => PCH_PP_CONTROL_BACKLIGHT_ENABLE);
    end Backlight_On;
 
    procedure Backlight_Off (Panel : Panel_Control) is
@@ -443,14 +443,14 @@
 
       pragma Debug (Debug.Put_Line (GNAT.Source_Info.Enclosing_Entity));
 
+     Registers.Unset_Mask
+       (Register => PP (Panel).CONTROL,
+        Mask     => PCH_PP_CONTROL_BACKLIGHT_ENABLE);
+
       if Config.Has_New_Backlight_Control then
          Registers.Unset_Mask
            (Register => BLC (Panel).CTL,
             Mask     => BXT_BLC_PWM_CTL_ENABLE);
-      else
-         Registers.Unset_Mask
-           (Register => PP (Panel).CONTROL,
-            Mask     => PCH_PP_CONTROL_BACKLIGHT_ENABLE);
       end if;
    end Backlight_Off;