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.lisovskiy@xxxxxxxxx> --- 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