[PATCH 03/11] apple-gmux: Add switch_ddc support

[Lukas Wunner]

From: Seth Forshee <seth.forshee at canonical.com>

The gmux allows muxing the DDC independently from the display, so
support this functionality. This will allow reading the EDID for the
inactive GPU, fixing issues with machines that either don't have a VBT
or have invalid mode data in the VBT.

Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
Signed-off-by: Dave Airlie <airlied at gmail.com>
Signed-off-by: Lukas Wunner <lukas at wunner.de>
---
 drivers/platform/x86/apple-gmux.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index b9429fb..1cf242c 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -271,14 +271,21 @@ static const struct backlight_ops gmux_bl_ops = {
 	.update_status = gmux_update_status,
 };
 
+static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
+{
+	if (id == VGA_SWITCHEROO_IGD)
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
+	else
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
+	return 0;
+}
+
 static int gmux_switchto(enum vga_switcheroo_client_id id)
 {
 	if (id == VGA_SWITCHEROO_IGD) {
-		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
 		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
 		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
 	} else {
-		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
 		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
 		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
 	}
@@ -345,6 +352,7 @@ gmux_active_client(struct apple_gmux_data *gmux_data)
 }
 
 static struct vga_switcheroo_handler gmux_handler = {
+	.switch_ddc = gmux_switch_ddc,
 	.switchto = gmux_switchto,
 	.power_state = gmux_set_power_state,
 	.get_client_id = gmux_get_client_id,
-- 
1.8.5.2 (Apple Git-48)