On Fri, 2015-10-30 at 18:47 +0200, [email protected] wrote: > 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.
Does the device NACKs the request? Ander > > 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; > } --------------------------------------------------------------------- Intel Finland Oy Registered Address: PL 281, 00181 Helsinki Business Identity Code: 0357606 - 4 Domiciled in Helsinki This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies. _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
