drm/i915: Disable live M/N updates when using bigjoiner

All joined pipes share the same transcoder/timing generator.
Currently we just do the commits per-pipe, which doesn't really
work if we need to change the timings at the same time. For
now just disable live M/N updates when bigjoiner is needed.

Cc: stable@vger.kernel.org
Tested-by: Vidya Srinivas <vidya.srinivas@intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404213441.17637-5-ville.syrjala@linux.intel.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
(cherry picked from commit ef79820db723a2a7c229a7251c12859e7e25a247)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index abd62bebc46d0e58d5bc78d8f4500ddcbc6098f1..e583515f9b25a33da4825d10cf42a9f73fa17990 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2725,7 +2725,11 @@ intel_dp_drrs_compute_config(struct intel_connector *connector,
                intel_panel_downclock_mode(connector, &pipe_config->hw.adjusted_mode);
        int pixel_clock;
 
-       if (has_seamless_m_n(connector))
+       /*
+        * FIXME all joined pipes share the same transcoder.
+        * Need to account for that when updating M/N live.
+        */
+       if (has_seamless_m_n(connector) && !pipe_config->bigjoiner_pipes)
                pipe_config->update_m_n = true;
 
        if (!can_enable_drrs(connector, pipe_config, downclock_mode)) {