[PATCH v2 1/2] drm/i915/mso: using joiner is not possible with eDP MSO

[Jani Nikula]

It's not possible to use the joiner at the same time with eDP MSO. When
a panel needs MSO, it's not optional, so MSO trumps joiner.

While just reporting false for intel_dp_has_joiner() should be
sufficient, also skip creation of the joiner force enable debugfs to
better handle this in testing.

Cc: stable at vger.kernel.org
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1668
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_debugfs.c | 8 ++++++--
 drivers/gpu/drm/i915/display/intel_dp.c              | 4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index 91757fed9c6d..5eb31404436c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -1546,8 +1546,12 @@ void intel_connector_debugfs_add(struct intel_connector *connector)
 	if (DISPLAY_VER(i915) >= 11 &&
 	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
 	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
-		debugfs_create_bool("i915_bigjoiner_force_enable", 0644, root,
-				    &connector->force_bigjoiner_enable);
+		struct intel_dp *intel_dp = intel_attached_dp(connector);
+
+		/* eDP MSO is not compatible with joiner */
+		if (!intel_dp->mso_link_count)
+			debugfs_create_bool("i915_bigjoiner_force_enable", 0644, root,
+					    &connector->force_bigjoiner_enable);
 	}
 
 	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9a9bb0f5b7fe..ab33c9de393a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -465,6 +465,10 @@ bool intel_dp_has_joiner(struct intel_dp *intel_dp)
 	struct intel_encoder *encoder = &intel_dig_port->base;
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 
+	/* eDP MSO is not compatible with joiner */
+	if (intel_dp->mso_link_count)
+		return false;
+
 	return DISPLAY_VER(dev_priv) >= 12 ||
 		(DISPLAY_VER(dev_priv) == 11 &&
 		 encoder->port != PORT_A);
-- 
2.39.2