[PATCH 1/1] drm/i915: Allow bigjoiner for MST

[Vidya Srinivas]

We need bigjoiner support with MST functionality
for MST monitor resolutions > 5K to work.
Adding support for the same.

v2: Addressed review comments from Jani.
Revert rejection of MST bigjoiner modes and add
functionality

v3: Fixed pipe_mismatch WARN for mst_master_transcoder
Credits-to: Manasi Navare <navaremanasi at chromium.org>

Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c    |  6 ++++--
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 17 +++++++++--------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index c587a8efeafc..41998022ed07 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3902,9 +3902,11 @@ static void intel_ddi_read_func_ctl(struct intel_encoder *encoder,
 		pipe_config->lane_count =
 			((temp & DDI_PORT_WIDTH_MASK) >> DDI_PORT_WIDTH_SHIFT) + 1;
 
-		if (DISPLAY_VER(dev_priv) >= 12)
-			pipe_config->mst_master_transcoder =
+		if (DISPLAY_VER(dev_priv) >= 12) {
+			if (!intel_crtc_is_bigjoiner_slave(pipe_config))
+				pipe_config->mst_master_transcoder =
 					REG_FIELD_GET(TRANS_DDI_MST_TRANSPORT_SELECT_MASK, temp);
+		}
 
 		intel_cpu_transcoder_get_m1_n1(crtc, cpu_transcoder,
 					       &pipe_config->dp_m_n);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index db1254b036f1..c5e7293c13eb 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -525,6 +525,7 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_atomic_state *state = to_intel_atomic_state(conn_state->state);
+	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
 	struct intel_dp *intel_dp = &intel_mst->primary->dp;
 	const struct intel_connector *connector =
@@ -542,6 +543,10 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
 	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return -EINVAL;
 
+	if (intel_dp_need_bigjoiner(intel_dp, adjusted_mode->crtc_hdisplay,
+				    adjusted_mode->crtc_clock))
+		pipe_config->bigjoiner_pipes = GENMASK(crtc->pipe + 1, crtc->pipe);
+
 	pipe_config->sink_format = INTEL_OUTPUT_FORMAT_RGB;
 	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
 	pipe_config->has_pch_encoder = false;
@@ -1330,12 +1335,6 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
 	 *   corresponding link capabilities of the sink) in case the
 	 *   stream is uncompressed for it by the last branch device.
 	 */
-	if (mode_rate > max_rate || mode->clock > max_dotclk ||
-	    drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
-		*status = MODE_CLOCK_HIGH;
-		return 0;
-	}
-
 	if (mode->clock < 10000) {
 		*status = MODE_CLOCK_LOW;
 		return 0;
@@ -1349,8 +1348,10 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
 	if (intel_dp_need_bigjoiner(intel_dp, mode->hdisplay, target_clock)) {
 		bigjoiner = true;
 		max_dotclk *= 2;
+	}
 
-		/* TODO: add support for bigjoiner */
+	if (mode_rate > max_rate || mode->clock > max_dotclk ||
+	    drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
 		*status = MODE_CLOCK_HIGH;
 		return 0;
 	}
@@ -1397,7 +1398,7 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
 		return 0;
 	}
 
-	*status = intel_mode_valid_max_plane_size(dev_priv, mode, false);
+	*status = intel_mode_valid_max_plane_size(dev_priv, mode, bigjoiner);
 	return 0;
 }
 
-- 
2.33.0