commit 1bc496fc832cde66cad36d299cb4f193775a26a4
author Nico Huber <nico.h@gmx.de> Fri Jun 09 22:23:28 2017 +0200
committer Nico Huber <nico.h@gmx.de> Mon Aug 28 20:12:45 2017 +0000
tree 68777156972175b157b5fe279ac26ac03b24ac41
parent c3f66f635352be8f49da55f2727a6fc3093d7e62

gma-display_probing: Only check display type on DVI-I

On DVI-I connectors the DDC is shared between the analog and digital
parts. To decide which path to take we checked the digital input bit
of the EDID. We did this overeagerly for all ports, which broke com-
patibility with DP adapters (the DP realm is very complex and we are
supposed to discover the whole downstream hierarchie, which obviously
would be overkill).

Change-Id: Ifc53e8ab985695e6e4ff1d42659826710a50eae9
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/20135
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

common/hw-gfx-gma-config.ads.template

diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template
index b4e52f6..e82b133 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -39,6 +39,7 @@
 
    Has_Internal_Display    : constant Boolean := Internal_Display /= None;
    Internal_Is_EDP         : constant Boolean := Internal_Display = DP;
+   Have_DVI_I              : constant Boolean := Analog_I2C_Port /= PCH_DAC;
    Has_Presence_Straps     : constant Boolean := CPU /= Broxton;
 
    ----- CPU pipe: --------

common/hw-gfx-gma-display_probing.adb

diff --git a/common/hw-gfx-gma-display_probing.adb b/common/hw-gfx-gma-display_probing.adb
index 97792cf..96cf536 100644
--- a/common/hw-gfx-gma-display_probing.adb
+++ b/common/hw-gfx-gma-display_probing.adb
@@ -61,6 +61,16 @@
       return Sibling_Port (Port) /= Disabled;
    end Has_Sibling_Port;
 
+   function Is_DVI_I (Port : Active_Port_Type) return Boolean
+   with
+      Global => null
+   is
+   begin
+      return Config.Have_DVI_I and
+             (Port = Analog or
+              Config_Helpers.To_PCH_Port (Port) = Config.Analog_I2C_Port);
+   end Is_DVI_I;
+
    procedure Read_EDID
      (Raw_EDID :    out EDID.Raw_EDID_Data;
       Port     : in     Active_Port_Type;
@@ -134,8 +144,8 @@
       end if;
 
       if Success and then
-         (EDID.Compatible_Display
-            (Raw_EDID, Config_Helpers.To_Display_Type (Port)) and
+         ((not Is_DVI_I (Port) or EDID.Compatible_Display
+            (Raw_EDID, Config_Helpers.To_Display_Type (Port))) and
           EDID.Has_Preferred_Mode (Raw_EDID))
       then
          Pipe_Cfg.Port := Port;