1 files changed, 42 insertions, 3 deletions

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 5c6c708e56b8..1384a393f2f7 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -417,6 +417,25 @@ static int gmux_switchto(enum vga_switcheroo_client_id id)
 	return 0;
 }
 
+static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
+{
+	enum vga_switcheroo_client_id old_ddc_owner =
+		apple_gmux_data->switch_state_ddc;
+
+	if (id == old_ddc_owner)
+		return id;
+
+	pr_debug("Switching DDC from %d to %d\n", old_ddc_owner, id);
+	apple_gmux_data->switch_state_ddc = 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 old_ddc_owner;
+}
+
 /**
  * DOC: Power control
  *
@@ -474,12 +493,19 @@ static int gmux_get_client_id(struct pci_dev *pdev)
 		return VGA_SWITCHEROO_DIS;
 }
 
-static const struct vga_switcheroo_handler gmux_handler = {
+static const struct vga_switcheroo_handler gmux_handler_indexed = {
 	.switchto = gmux_switchto,
 	.power_state = gmux_set_power_state,
 	.get_client_id = gmux_get_client_id,
 };
 
+static const struct vga_switcheroo_handler gmux_handler_classic = {
+	.switchto = gmux_switchto,
+	.switch_ddc = gmux_switch_ddc,
+	.power_state = gmux_set_power_state,
+	.get_client_id = gmux_get_client_id,
+};
+
 /**
  * DOC: Interrupt
  *
@@ -730,8 +756,21 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 	gmux_enable_interrupts(gmux_data);
 	gmux_read_switch_state(gmux_data);
 
-	if (vga_switcheroo_register_handler(&gmux_handler, 0)) {
-		ret = -ENODEV;
+	/*
+	 * Retina MacBook Pros cannot switch the panel's AUX separately
+	 * and need eDP pre-calibration. They are distinguishable from
+	 * pre-retinas by having an "indexed" gmux.
+	 *
+	 * Pre-retina MacBook Pros can switch the panel's DDC separately.
+	 */
+	if (gmux_data->indexed)
+		ret = vga_switcheroo_register_handler(&gmux_handler_indexed,
+					      VGA_SWITCHEROO_NEEDS_EDP_CONFIG);
+	else
+		ret = vga_switcheroo_register_handler(&gmux_handler_classic,
+					      VGA_SWITCHEROO_CAN_SWITCH_DDC);
+	if (ret) {
+		pr_err("Failed to register vga_switcheroo handler\n");
 		goto err_register_handler;
 	}