drm/nouveau/disp/dp: respect sink limits when selecting failsafe link configuration

[ Upstream commit 13d03e9daf70dab032c03dc172e75bb98ad899c4 ]

Where possible, we want the failsafe link configuration (one which won't
hang the OR during modeset because of not enough bandwidth for the mode)
to also be supported by the sink.

This prevents "link rate unsupported by sink" messages when link training
fails.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
index 6160a6158cf26c9c33539fbd8cdc45e4e0ec63ff..5e51a5c1eb013b0847646c3f7a6063ce1831df2c 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
@@ -364,8 +364,15 @@ nvkm_dp_train(struct nvkm_dp *dp, u32 dataKBps)
         * and it's better to have a failed modeset than that.
         */
        for (cfg = nvkm_dp_rates; cfg->rate; cfg++) {
-               if (cfg->nr <= outp_nr && cfg->nr <= outp_bw)
-                       failsafe = cfg;
+               if (cfg->nr <= outp_nr && cfg->nr <= outp_bw) {
+                       /* Try to respect sink limits too when selecting
+                        * lowest link configuration.
+                        */
+                       if (!failsafe ||
+                           (cfg->nr <= sink_nr && cfg->bw <= sink_bw))
+                               failsafe = cfg;
+               }
+
                if (failsafe && cfg[1].rate < dataKBps)
                        break;
        }