[SRU][R][PATCH v2 02/12] drm/i915/dp: Avoid joiner for eDP if not enabled in VBT

[Werner Sembach]

From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>

For eDP, enable the Pipe Joiner feature only if VBT explicitly allows it.
If VBT disables the feature, skip joiner for eDP, even if the hardware
supports it.

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14616
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>
Link: https://patch.msgid.link/20260108124141.1407760-3-ankit.k.nautiyal@intel.com
Signed-off-by: Werner Sembach <wse at tuxedocomputers.com>
(cherry picked from commit 650471948e495204f1f89731c71bcf48b3f81b08)
Signed-off-by: Werner Sembach <wse at tuxedocomputers.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 696edf40b2436..6f62de475ee75 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -508,11 +508,16 @@ bool intel_dp_has_joiner(struct intel_dp *intel_dp)
 	struct intel_display *display = to_intel_display(intel_dp);
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	struct intel_encoder *encoder = &intel_dig_port->base;
+	struct intel_connector *connector = intel_dp->attached_connector;
 
 	/* eDP MSO is not compatible with joiner */
 	if (intel_dp->mso_link_count)
 		return false;
 
+	if (intel_dp_is_edp(intel_dp) &&
+	    !connector->panel.vbt.edp.pipe_joiner_enable)
+		return false;
+
 	return DISPLAY_VER(display) >= 12 ||
 		(DISPLAY_VER(display) == 11 &&
 		 encoder->port != PORT_A);
-- 
2.43.0