drm/i915: Extend hotplug detect retry on TypeC connectors to 5 seconds

On TypeC ports if a sink deasserts/reasserts its HPD signal, generating
a hotplug interrupt without the sink getting unplugged/replugged from
the connector, there can be an up to 3 seconds delay until the AUX
channel gets functional. To avoid detection failures this delay causes
retry the detection for 5 seconds.

I noticed this on ICL/TGL RVPs and a DELL XPS 13 7390 ICL laptop.

References: https://gitlab.freedesktop.org/drm/intel/issues/1067
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200330095425.29113-2-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 1bc6bfb..be6c61b 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4520,7 +4520,10 @@ static enum intel_hotplug_state
 intel_ddi_hotplug(struct intel_encoder *encoder,
                  struct intel_connector *connector)
 {
+       struct drm_i915_private *i915 = to_i915(encoder->base.dev);
        struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
+       enum phy phy = intel_port_to_phy(i915, encoder->port);
+       bool is_tc = intel_phy_is_tc(i915, phy);
        struct drm_modeset_acquire_ctx ctx;
        enum intel_hotplug_state state;
        int ret;
@@ -4563,8 +4566,15 @@ intel_ddi_hotplug(struct intel_encoder *encoder,
         * valid EDID. To solve this schedule another detection cycle if this
         * time around we didn't detect any change in the sink's connection
         * status.
+        *
+        * Type-c connectors which get their HPD signal deasserted then
+        * reasserted, without unplugging/replugging the sink from the
+        * connector, introduce a delay until the AUX channel communication
+        * becomes functional. Retry the detection for 5 seconds on type-c
+        * connectors to account for this delay.
         */
-       if (state == INTEL_HOTPLUG_UNCHANGED && !connector->hotplug_retries &&
+       if (state == INTEL_HOTPLUG_UNCHANGED &&
+           connector->hotplug_retries < (is_tc ? 5 : 1) &&
            !dig_port->dp.is_mst)
                state = INTEL_HOTPLUG_RETRY;