On Tue, Mar 21, 2023 at 01:09:41PM +0200, Kahola, Mika wrote: > > -----Original Message----- > > From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Imre > > Deak > > Sent: Thursday, March 16, 2023 3:17 PM > > To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > Cc: Chris Chiu <chris.chiu@xxxxxxxxxxxxx> > > Subject: [PATCH 01/14] drm/i915/tc: Abort DP AUX transfer on a > > disconnected TC port > > > > 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. > > + */ > > + if (!intel_tc_port_connected_locked(&dig_port->base)) { > > + ret = -ENXIO; > > TC port being a physical object this error code could be ENODEV as well, right? The meaning of either error code is not defined precisely, but I interpreted ENXIO as a - temporary - error/non-presence of the remote device downstream of the port. There is another driver returning ENXIO for the same case. > Anyway, patch looks ok to me. > > Reviewed-by: Mika Kahola <mika.kahola@xxxxxxxxx> > > > + 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); > > -- > > 2.37.1 >
