2008-i915-4-lane-quirk-for-mbp15-1.patch

From 12c7a3306a631a651464ef56318a218dc4cdb157 Mon Sep 17 00:00:00 2001
From: Orlando Chamberlain <orlandoch.dev@gmail.com>
Date: Sat, 18 Feb 2023 23:05:05 +1100
Subject: [PATCH 8/9] i915: 4 lane quirk for mbp15,1

Needed to use iGPU when dGPU was boot GPU

Patch written by Kerem Karabay <kekrby@gmail.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c    |  3 +++
 drivers/gpu/drm/i915/display/intel_quirks.c | 15 +++++++++++++++
 drivers/gpu/drm/i915/display/intel_quirks.h |  1 +
 3 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 0f1ec2a98cc8..1ec67390f623 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4097,6 +4097,9 @@ static bool intel_ddi_a_force_4_lanes(struct intel_digital_port *dig_port)
 	if (dig_port->saved_port_bits & DDI_A_4_LANES)
 		return false;
 
+	if (intel_has_quirk(dev_priv, QUIRK_DDI_A_FORCE_4_LANES))
+		return true;
+
 	/* Broxton/Geminilake: Bspec says that DDI_A_4_LANES is the only
 	 *                     supported configuration
 	 */
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
index 6e48d3bcdfec..a8c55e165b46 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.c
+++ b/drivers/gpu/drm/i915/display/intel_quirks.c
@@ -59,6 +59,18 @@ static void quirk_increase_ddi_disabled_time(struct drm_i915_private *i915)
 	drm_info(&i915->drm, "Applying Increase DDI Disabled quirk\n");
 }
 
+/*
+ * In some cases, the firmware might not set the lane count to 4 (for example,
+ * when booting in some dual GPU Macs with the dGPU as the default GPU), this
+ * quirk is used to force it as otherwise it might not be possible to compute a
+ * valid link configuration.
+ */
+static void quirk_ddi_a_force_4_lanes(struct drm_i915_private *i915)
+{
+	intel_set_quirk(i915, QUIRK_DDI_A_FORCE_4_LANES);
+	drm_info(&i915->drm, "Applying DDI A Forced 4 Lanes quirk\n");
+}
+
 static void quirk_no_pps_backlight_power_hook(struct drm_i915_private *i915)
 {
 	intel_set_quirk(i915, QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK);
@@ -199,6 +211,9 @@ static struct intel_quirk intel_quirks[] = {
 	{ 0x3184, 0x1019, 0xa94d, quirk_increase_ddi_disabled_time },
 	/* HP Notebook - 14-r206nv */
 	{ 0x0f31, 0x103c, 0x220f, quirk_invert_brightness },
+
+	/* Apple MacBookPro15,1 */
+	{ 0x3e9b, 0x106b, 0x0176, quirk_ddi_a_force_4_lanes },
 };
 
 void intel_init_quirks(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.h b/drivers/gpu/drm/i915/display/intel_quirks.h
index 10a4d163149f..78aacf1f6f5c 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.h
+++ b/drivers/gpu/drm/i915/display/intel_quirks.h
@@ -17,6 +17,7 @@ enum intel_quirk_id {
 	QUIRK_INVERT_BRIGHTNESS,
 	QUIRK_LVDS_SSC_DISABLE,
 	QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK,
+	QUIRK_DDI_A_FORCE_4_LANES,
 };
 
 void intel_init_quirks(struct drm_i915_private *i915);
-- 
2.39.1