From: Ville Syrjälä <[email protected]> My Lenovo STM STDP3100 miniDP->VGA dongle doesn't seem to like it when we try to start link training with non-zero vswing/preemphasis. So when the initial link training DPCD write fails, retry it with zero values.
Fixes a bunch of errors like so: [drm:intel_dp_start_link_train [i915]] *ERROR* failed to enable link training Cc: Mika Kahola <[email protected]> Cc: Sivakumar Thulasimani <[email protected]> Cc: Ander Conselvan de Oliveira <[email protected]> Fixes: 5fa836a9d859 ("drm/i915: DP link training optimization") Signed-off-by: Ville Syrjälä <[email protected]> --- drivers/gpu/drm/i915/intel_dp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index ba4cbf5..9529a6e 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -3750,10 +3750,17 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) DP |= DP_PORT_EN; +again: /* clock recovery */ if (!intel_dp_reset_link_train(intel_dp, &DP, DP_TRAINING_PATTERN_1 | DP_LINK_SCRAMBLING_DISABLE)) { + if (intel_dp->train_set_valid) { + DRM_DEBUG_KMS("Sink rejected link training request, trying again with zero values\n"); + intel_dp->train_set_valid = false; + goto again; + } + DRM_ERROR("failed to enable link training\n"); return; } -- 2.4.10 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
