queue-4.14/drm-nouveau-disp-dp-respect-sink-limits-when-selecti.patch

   1 From 6c09c50009860a5803527c5f5961f619d81a169b Mon Sep 17 00:00:00 2001
   2 From: Ben Skeggs <bskeggs@redhat.com>
   3 Date: Fri, 10 May 2019 11:57:04 +1000
   4 Subject: drm/nouveau/disp/dp: respect sink limits when selecting failsafe link
   5  configuration
   6
   7 [ Upstream commit 13d03e9daf70dab032c03dc172e75bb98ad899c4 ]
   8
   9 Where possible, we want the failsafe link configuration (one which won't
  10 hang the OR during modeset because of not enough bandwidth for the mode)
  11 to also be supported by the sink.
  12
  13 This prevents "link rate unsupported by sink" messages when link training
  14 fails.
  15
  16 Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
  17 Signed-off-by: Sasha Levin <sashal@kernel.org>
  18 ---
  19  drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c | 11 +++++++++--
  20  1 file changed, 9 insertions(+), 2 deletions(-)
  21
  22 diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
  23 index 6160a6158cf2..5e51a5c1eb01 100644
  24 --- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
  25 +++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
  26 @@ -364,8 +364,15 @@ nvkm_dp_train(struct nvkm_dp *dp, u32 dataKBps)
  27          * and it's better to have a failed modeset than that.
  28          */
  29         for (cfg = nvkm_dp_rates; cfg->rate; cfg++) {
  30 -               if (cfg->nr <= outp_nr && cfg->nr <= outp_bw)
  31 -                       failsafe = cfg;
  32 +               if (cfg->nr <= outp_nr && cfg->nr <= outp_bw) {
  33 +                       /* Try to respect sink limits too when selecting
  34 +                        * lowest link configuration.
  35 +                        */
  36 +                       if (!failsafe ||
  37 +                           (cfg->nr <= sink_nr && cfg->bw <= sink_bw))
  38 +                               failsafe = cfg;
  39 +               }
  40 +
  41                 if (failsafe && cfg[1].rate < dataKBps)
  42                         break;
  43         }
  44 --
  45 2.20.1
  46