[RFC PATCH 1/1] drm/i915/display: Avoid unsupported 300Hz output mode on a TUXEDO device

[Werner Sembach <wse@tuxedocomputers.com>]

From: Tim Guttzeit <t.guttzeit@tuxedocomputers.com>

Removes all display modes with more than 240 Hz for the integrated display
on a TUXEDO Stellaris 16 Gen7, because using the iGPU with higer refresh
rates causes screen flicker.

Signed-off-by: Tim Guttzeit <t.guttzeit@tuxedocomputers.com>
Co-developed-by: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c     |  5 ++++
 drivers/gpu/drm/i915/display/intel_quirks.c | 30 +++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_quirks.h |  1 +
 3 files changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 640c43bf62d4c..5ce00cfe36ee1 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1436,6 +1436,11 @@ intel_dp_mode_valid(struct drm_connector *_connector,
 	if (mode->clock < 10000)
 		return MODE_CLOCK_LOW;
 
+	if (intel_has_quirk(display, QUIRK_EDP_MAX_240HZ_HOOK) &&
+	    intel_dp_is_edp(intel_dp) &&
+	    drm_mode_vrefresh(mode) > 240)
+		return MODE_BAD;
+
 	fixed_mode = intel_panel_fixed_mode(connector, mode);
 	if (intel_dp_is_edp(intel_dp) && fixed_mode) {
 		status = intel_panel_mode_valid(connector, mode);
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
index a32fae510ed27..438ce2cb37a01 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.c
+++ b/drivers/gpu/drm/i915/display/intel_quirks.c
@@ -72,6 +72,12 @@ static void quirk_no_pps_backlight_power_hook(struct intel_display *display)
 	drm_info(display->drm, "Applying no pps backlight power quirk\n");
 }
 
+static void quirk_edp_max_240hz_hook(struct intel_display *display)
+{
+	intel_set_quirk(display, QUIRK_EDP_MAX_240HZ_HOOK);
+	drm_info(display->drm, "Applying max 240Hz quirk\n");
+}
+
 static void quirk_fw_sync_len(struct intel_dp *intel_dp)
 {
 	struct intel_display *display = to_intel_display(intel_dp);
@@ -120,6 +126,12 @@ static int intel_dmi_no_pps_backlight(const struct dmi_system_id *id)
 	return 1;
 }
 
+static int intel_dmi_edp_max_240hz(const struct dmi_system_id *id)
+{
+	DRM_INFO("Restrict output refreshrate to maximum 240Hz %s\n", id->ident);
+	return 1;
+}
+
 static const struct intel_dmi_quirk intel_dmi_quirks[] = {
 	{
 		.dmi_id_list = &(const struct dmi_system_id[]) {
@@ -166,6 +178,24 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = {
 		},
 		.hook = quirk_no_pps_backlight_power_hook,
 	},
+	{
+		.dmi_id_list = &(const struct dmi_system_id[]) {
+			{
+				.callback = intel_dmi_edp_max_240hz,
+				.ident = "TUXEDO Stellaris 16 Intel Gen7",
+				.matches = {DMI_EXACT_MATCH(DMI_BOARD_NAME, "X6AR5xxY"),
+				},
+			},
+			{
+				.callback = intel_dmi_edp_max_240hz,
+				.ident = "TUXEDO Stellaris 16 Intel Gen7",
+				.matches = {DMI_EXACT_MATCH(DMI_BOARD_NAME, "X6AR5xxY_mLED"),
+				},
+			},
+			{ }
+		},
+		.hook = quirk_edp_max_240hz_hook,
+	},
 };
 
 static struct intel_quirk intel_quirks[] = {
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.h b/drivers/gpu/drm/i915/display/intel_quirks.h
index cafdebda75354..8fe3f3467106a 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.h
+++ b/drivers/gpu/drm/i915/display/intel_quirks.h
@@ -20,6 +20,7 @@ enum intel_quirk_id {
 	QUIRK_LVDS_SSC_DISABLE,
 	QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK,
 	QUIRK_FW_SYNC_LEN,
+	QUIRK_EDP_MAX_240HZ_HOOK,
 };
 
 void intel_init_quirks(struct intel_display *display);
-- 
2.43.0