commit 393aa8a8b62455d69651122d1aa3dacc21dd750c
author Nico Huber <nico.huber@secunet.com> Fri Oct 21 14:18:53 2016 +0200
committer Nico Huber <nico.h@gmx.de> Sat Oct 29 01:24:23 2016 +0200
tree 88b06915c9a42a3c7a85682620ad3647a625aa8d
parent abe3de257c482ebeb90cf9f93d69ae744c60f9a6

gma edid: Check expected display type

Check that the EDID's digital-input bit matches the expected display
type (i.e. it should only be set for non-VGA displays).

Change-Id: I099112f190f866525e882d5e24a428092d4d8331
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/17085
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

common/hw-gfx-edid.adb

diff --git a/common/hw-gfx-edid.adb b/common/hw-gfx-edid.adb
index 64b86a9..44d729f 100644
--- a/common/hw-gfx-edid.adb
+++ b/common/hw-gfx-edid.adb
@@ -68,6 +68,15 @@
 
    ----------------------------------------------------------------------------
 
+   function Compatible_Display
+     (Raw_EDID : Raw_EDID_Data;
+      Display  : Display_Type)
+      return Boolean
+   is
+   begin
+      return (Display = VGA) = ((Raw_EDID (INPUT) and INPUT_DIGITAL) = 16#00#);
+   end Compatible_Display;
+
    function Read_LE16
      (Raw_EDID : Raw_EDID_Data;
       Offset   : Raw_EDID_Index)

common/hw-gfx-edid.ads

diff --git a/common/hw-gfx-edid.ads b/common/hw-gfx-edid.ads
index efc3b36..cce1a40 100644
--- a/common/hw-gfx-edid.ads
+++ b/common/hw-gfx-edid.ads
@@ -32,6 +32,13 @@
    with
       Pre => Offset < Raw_EDID_Index'Last;
 
+   function Compatible_Display
+     (Raw_EDID : Raw_EDID_Data;
+      Display  : Display_Type)
+      return Boolean
+   with
+      Pre => Valid (Raw_EDID);
+
    function Has_Preferred_Mode (Raw_EDID : Raw_EDID_Data) return Boolean
    with
       Pre => Valid (Raw_EDID),

common/hw-gfx-gma.adb

diff --git a/common/hw-gfx-gma.adb b/common/hw-gfx-gma.adb
index 416117b..cd202be 100644
--- a/common/hw-gfx-gma.adb
+++ b/common/hw-gfx-gma.adb
@@ -327,7 +327,10 @@
                   Connector_Info.Read_EDID (Raw_EDID, Port_Cfg, Success);
                end if;
 
-               if Success and then EDID.Has_Preferred_Mode (Raw_EDID) then
+               if Success and then
+                  (EDID.Compatible_Display (Raw_EDID, Port_Cfg.Display) and
+                   EDID.Has_Preferred_Mode (Raw_EDID))
+               then
                   Configs (Config_Idx).Mode := EDID.Preferred_Mode (Raw_EDID);
                else
                   Configs (Config_Idx).Port := Disabled;
@@ -428,7 +431,10 @@
                   Success  => Success);
             end if;
 
-            if Success and then EDID.Has_Preferred_Mode (Raw_EDID) then
+            if Success and then
+               (EDID.Compatible_Display (Raw_EDID, Port_Cfg.Display) and
+                EDID.Has_Preferred_Mode (Raw_EDID))
+            then
                Configs (Config_Idx) := Config_Type'
                  (Port        => Port,
                   Framebuffer => Configs (Config_Idx).Framebuffer,

common/hw-gfx-gma.ads

diff --git a/common/hw-gfx-gma.ads b/common/hw-gfx-gma.ads
index 3adf1f9..1e64cb4 100644
--- a/common/hw-gfx-gma.ads
+++ b/common/hw-gfx-gma.ads
@@ -109,10 +109,6 @@
    subtype PCH_HDMI_Port is PCH_Port range PCH_HDMI_B .. PCH_HDMI_D;
    subtype PCH_DP_Port is PCH_Port range PCH_DP_B .. PCH_DP_D;
 
-   type Display_Type is (None, LVDS, DP, HDMI, VGA);
-
-   subtype Internal_Type is Display_Type range None .. DP;
-
    type Port_Config is
       record
          Port     : GPU_Port;

common/hw-gfx.ads

diff --git a/common/hw-gfx.ads b/common/hw-gfx.ads
index b9d7225..051b326 100644
--- a/common/hw-gfx.ads
+++ b/common/hw-gfx.ads
@@ -94,6 +94,9 @@
       Enhanced_Framing        => False,
       Opportunistic_Training  => False);
 
+   type Display_Type is (None, LVDS, DP, HDMI, VGA);
+   subtype Internal_Type is Display_Type range None .. DP;
+
    type Mode_Type is
    record
       Dotclock             : Frequency_Type;