We currently always exit that bpp loop because drm_dp_atomic_find_vcpi_slots
doesn't care if we actually can fit those or not.
I think that wasn't the initial intention here, especially when
we keep trying with lower bpps, we are supposed to keep trying
until we actually find some _working_ configuration, which isn't the
case here.
So added that drm_dp_mst_check here, so that we can make sure
that try all the bpps before we fail.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovs...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c 
b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 14d2a64193b2..c61fd8b39c27 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -59,6 +59,7 @@ static int intel_dp_mst_compute_link_config(struct 
intel_encoder *encoder,
                &crtc_state->hw.adjusted_mode;
        bool constant_n = drm_dp_has_quirk(&intel_dp->desc, 
DP_DPCD_QUIRK_CONSTANT_N);
        int bpp, slots = -EINVAL;
+       int ret = 0;
 
        crtc_state->lane_count = limits->max_lane_count;
        crtc_state->port_clock = limits->max_rate;
@@ -78,10 +79,21 @@ static int intel_dp_mst_compute_link_config(struct 
intel_encoder *encoder,
                                                                               
crtc_state->lane_count));
                if (slots == -EDEADLK)
                        return slots;
-               if (slots >= 0)
-                       break;
+               if (slots >= 0) {
+                       ret = drm_dp_mst_atomic_check(state);
+                       /*
+                        * If we got slots >= 0 and we can fit those based on 
check
+                        * then we can exit the loop. Otherwise keep trying.
+                        */
+                       if (!ret)
+                               break;
+               }
        }
 
+       /* Despite slots are non-zero, we still failed the atomic check */
+       if (ret && slots >= 0)
+               slots = ret;
+
        if (slots < 0) {
                drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
                            slots);
-- 
2.24.1.485.gad05a3d8e5

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