[RFC v3 15/15] drm/i915/dp: compute config for 128b/132b SST w/o DSC

[Imre Deak]

From: Jani Nikula <jani.nikula at intel.com>

Enable basic 128b/132b SST functionality without compression. Reuse
intel_dp_mtp_tu_compute_config() to figure out the TU after we've
determined we need to use an UHBR rate.

It's slightly complicated as the M/N computation is done in different
places in MST and SST paths, so we need to avoid trashing the values
later for UHBR.

If uncompressed UHBR fails, we drop to compressed non-UHBR, which is
quite likely to fail as well. We still lack 128b/132b SST+DSC.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index dc84979d32947..6be83103099d8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2525,8 +2525,8 @@ intel_dp_compute_config_limits(struct intel_dp *intel_dp,
 	limits->min_rate = intel_dp_min_link_rate(intel_dp);
 	limits->max_rate = intel_dp_max_link_rate(intel_dp);
 
-	/* FIXME 128b/132b SST support missing */
-	if (!is_mst)
+	/* FIXME 128b/132b SST+DSC support missing */
+	if (!is_mst && dsc)
 		limits->max_rate = min(limits->max_rate, 810000);
 	limits->min_rate = min(limits->min_rate, limits->max_rate);
 
@@ -2640,6 +2640,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 		 */
 		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
 							conn_state, &limits);
+		if (!ret && intel_dp_is_uhbr(pipe_config))
+			ret = intel_dp_mtp_tu_compute_config(intel_dp,
+							     pipe_config,
+							     pipe_config->pipe_bpp,
+							     pipe_config->pipe_bpp,
+							     conn_state,
+							     0, false);
 		if (ret)
 			dsc_needed = true;
 	}
@@ -3184,12 +3191,14 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	intel_dp_audio_compute_config(encoder, pipe_config, conn_state);
 
-	intel_link_compute_m_n(link_bpp_x16,
-			       pipe_config->lane_count,
-			       adjusted_mode->crtc_clock,
-			       pipe_config->port_clock,
-			       intel_dp_bw_fec_overhead(pipe_config->fec_enable),
-			       &pipe_config->dp_m_n);
+	if (!intel_dp_is_uhbr(pipe_config)) {
+		intel_link_compute_m_n(link_bpp_x16,
+				       pipe_config->lane_count,
+				       adjusted_mode->crtc_clock,
+				       pipe_config->port_clock,
+				       intel_dp_bw_fec_overhead(pipe_config->fec_enable),
+				       &pipe_config->dp_m_n);
+	}
 
 	/* FIXME: abstract this better */
 	if (pipe_config->splitter.enable)
-- 
2.44.2