On Wed, Mar 22, 2023 at 12:19:26PM +0100, Andrzej Hajda wrote: > On 16.03.2023 14:17, Imre Deak wrote: > > On TC ports the 4ms AUX timeout combined with the 5 * 32 retry > > attempts during DPCD accesses adds a 640ms delay to each access if the > > sink is disconnected. This in turn slows down a modeset during which the > > sink is disconnected (for instance a disabling modeset). > > > > Prevent the above delay by aborting AUX transfers on a TC port with a > > disconnected sink. > > > > The DP 1.4a link CTS (4.2.1.5 Source Device Inactive HPD / Inactive AUX > > Test") also requires not to initiate AUX transfers on disconnected DP > > ports in general, however this patch doesn't change the behavior on > > non-TC ports, leaving that for a follow-up. > > > > Reported-and-tested-by: Chris Chiu <chris.chiu@xxxxxxxxxxxxx> > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8279 > > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++++++++++-- > > drivers/gpu/drm/i915/display/intel_tc.c | 15 +++++++++++---- > > drivers/gpu/drm/i915/display/intel_tc.h | 1 + > > 3 files changed, 25 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c > > index 96967e21c94c2..eb07dc5d87099 100644 > > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c > > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c > > @@ -205,8 +205,19 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp, > > for (i = 0; i < ARRAY_SIZE(ch_data); i++) > > ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i); > > - if (is_tc_port) > > + if (is_tc_port) { > > intel_tc_port_lock(dig_port); > > + /* > > + * Abort transfers on a disconnected port as required by > > + * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX > > + * timeouts that would otherwise happen. > > + * TODO: abort the transfer on non-TC ports as well. > > Yes, for all ports this is definitely desirable, for example grep shows > about 15000 timeouts per one CI dmesg[1]. > > At least I hope, this cures the plague. Looks like a different scenario where HDMI and DP share the same HPD pin. > Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx> Thanks. > > [1]: > http://gfx-ci.igk.intel.com/tree/drm-tip/CI_DRM_12884/fi-elk-e7500/dmesg0.txt > > Regards > Andrzej > > > > + */ > > + if (!intel_tc_port_connected_locked(&dig_port->base)) { > > + ret = -ENXIO; > > + goto out_unlock; > > + } > > + } > > aux_domain = intel_aux_power_domain(dig_port); > > @@ -367,7 +378,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp, > > intel_pps_unlock(intel_dp, pps_wakeref); > > intel_display_power_put_async(i915, aux_domain, aux_wakeref); > > - > > +out_unlock: > > if (is_tc_port) > > intel_tc_port_unlock(dig_port); > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c > > index f45328712bff1..050f998284592 100644 > > --- a/drivers/gpu/drm/i915/display/intel_tc.c > > +++ b/drivers/gpu/drm/i915/display/intel_tc.c > > @@ -768,16 +768,23 @@ void intel_tc_port_sanitize_mode(struct intel_digital_port *dig_port) > > * connected ports are usable, and avoids exposing to the users objects they > > * can't really use. > > */ > > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder) > > +{ > > + struct intel_digital_port *dig_port = enc_to_dig_port(encoder); > > + struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev); > > + > > + drm_WARN_ON(&i915->drm, !intel_tc_port_ref_held(dig_port)); > > + > > + return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode); > > +} > > + > > bool intel_tc_port_connected(struct intel_encoder *encoder) > > { > > struct intel_digital_port *dig_port = enc_to_dig_port(encoder); > > bool is_connected; > > intel_tc_port_lock(dig_port); > > - > > - is_connected = tc_port_live_status_mask(dig_port) & > > - BIT(dig_port->tc_mode); > > - > > + is_connected = intel_tc_port_connected_locked(encoder); > > intel_tc_port_unlock(dig_port); > > return is_connected; > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.h b/drivers/gpu/drm/i915/display/intel_tc.h > > index d54082e2d5e8d..93813056043a5 100644 > > --- a/drivers/gpu/drm/i915/display/intel_tc.h > > +++ b/drivers/gpu/drm/i915/display/intel_tc.h > > @@ -17,6 +17,7 @@ bool intel_tc_port_in_dp_alt_mode(struct intel_digital_port *dig_port); > > bool intel_tc_port_in_legacy_mode(struct intel_digital_port *dig_port); > > bool intel_tc_port_connected(struct intel_encoder *encoder); > > +bool intel_tc_port_connected_locked(struct intel_encoder *encoder); > > u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port); > > u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port *dig_port); >
