On Fri, 2020-06-05 at 12:48 +0300, Imre Deak wrote: > Currently MST on a port can get enabled/disabled from the hotplug work > and get disabled from the short pulse work in a racy way. Fix this by > relying on the MST state checking in the hotplug work and just schedule > a hotplug work from the short pulse handler if some problem happened > during the MST interrupt handling. > > This removes the explicit MST disabling in case of an AUX failure, but > if AUX fails, then probably the detection will also fail during the > scheduled hotplug work and it's not guaranteed that we'll see > intermittent errors anyway. > > While at it also simplify the error checking of the MST interrupt > handler. > > v2: > - Convert intel_dp_check_mst_status() to return bool. (Ville) > - Change the intel_dp->is_mst check to an assert, since after this patch > the condition can't change after we checked it previously. > - Document the return value from intel_dp_check_mst_status(). > v3: > - Remove the intel_dp->is_mst check from intel_dp_check_mst_status(). > There is no point in checking the same condition twice, even though > there is a chance that the hotplug work running concurrently changes > it. > > Cc: José Roberto de Souza <[email protected]> > Cc: Ville Syrjälä <[email protected]> > Reviewed-by: José Roberto de Souza <[email protected]> (v1) > Signed-off-by: Imre Deak <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 66 ++++++++++--------------- > 1 file changed, 26 insertions(+), 40 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index 55fda074c0ad..42589cae766d 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -5556,35 +5556,46 @@ static void intel_dp_handle_test_request(struct > intel_dp *intel_dp) > "Could not write test response to sink\n"); > } > > -static int > +/** > + * intel_dp_check_mst_status - service any pending MST interrupts, check > link status > + * @intel_dp: Intel DP struct > + * > + * Read any pending MST interrupts, call MST core to handle these and ack the > + * interrupts. Check if the main and AUX link state is ok. > + * > + * Returns: > + * - %true if pending interrupts were serviced (or no interrupts were > + * pending) w/o detecting an error condition. > + * - %false if an error condition - like AUX failure or a loss of link - is > + * detected, which needs servicing from the hotplug work. > + */ > +static bool > intel_dp_check_mst_status(struct intel_dp *intel_dp) > { > struct drm_i915_private *i915 = dp_to_i915(intel_dp); > - bool need_retrain = false; > - > - if (!intel_dp->is_mst) > - return -EINVAL; > + bool link_ok = true; > > drm_WARN_ON_ONCE(&i915->drm, intel_dp->active_mst_links < 0); > > for (;;) { > u8 esi[DP_DPRX_ESI_LEN] = {}; > - bool bret, handled; > + bool handled; > int retry; > > - bret = intel_dp_get_sink_irq_esi(intel_dp, esi); > - if (!bret) { > + if (!intel_dp_get_sink_irq_esi(intel_dp, esi)) { > drm_dbg_kms(&i915->drm, > "failed to get ESI - device may have > failed\n"); > - return -EINVAL; > + link_ok = false; > + > + break; > } > > /* check link status - esi[10] = 0x200c */ > - if (intel_dp->active_mst_links > 0 && !need_retrain && > + if (intel_dp->active_mst_links > 0 && link_ok && > !drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) { > drm_dbg_kms(&i915->drm, > "channel EQ not ok, retraining\n"); > - need_retrain = true; > + link_ok = false; > } > > drm_dbg_kms(&i915->drm, "got esi %3ph\n", esi); > @@ -5604,7 +5615,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) > } > } > > - return need_retrain; > + return link_ok; > } > > static bool > @@ -7255,35 +7266,10 @@ intel_dp_hpd_pulse(struct intel_digital_port > *intel_dig_port, bool long_hpd) > } > > if (intel_dp->is_mst) { > - switch (intel_dp_check_mst_status(intel_dp)) { > - case -EINVAL: > - /* > - * If we were in MST mode, and device is not > - * there, get out of MST mode > - */ > - drm_dbg_kms(&i915->drm, > - "MST device may have disappeared %d vs > %d\n", > - intel_dp->is_mst, > - intel_dp->mst_mgr.mst_state); > - intel_dp->is_mst = false; > - drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, > - intel_dp->is_mst); > - > - return IRQ_NONE; > - case 1: > - return IRQ_NONE; > - default: > - break; > - } > - } > - > - if (!intel_dp->is_mst) { > - bool handled; > - > - handled = intel_dp_short_pulse(intel_dp); > - > - if (!handled) > + if (!intel_dp_check_mst_status(intel_dp)) > return IRQ_NONE; > + } else if (!intel_dp_short_pulse(intel_dp)) { > + return IRQ_NONE; > } >
Now it don't need the braces but this is minor. Reviewed-by: José Roberto de Souza <[email protected]> > return IRQ_HANDLED; _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
