drm/i915/tc: Fix system resume MST mode restore for DP-alt sinks

From Imre Deak
1bdcffaa0d2c1dd0510d1b364c409e1c8fc96aa3 in linux-6.1.y/6.1.39
06f66261a1567d66b9d35c87393b6edfbea4c8f8 in mainline linux

diff --git a/sys/dev/pci/drm/i915/display/intel_display_types.h b/sys/dev/pci/drm/i915/display/intel_display_types.h
index bdc5d5e..73bdbe5 100644 (file)
--- a/sys/dev/pci/drm/i915/display/intel_display_types.h
+++ b/sys/dev/pci/drm/i915/display/intel_display_types.h
@@ -1763,6 +1763,7 @@ struct intel_digital_port {
        bool tc_legacy_port:1;
        char tc_port_name[8];
        enum tc_port_mode tc_mode;
+       enum tc_port_mode tc_init_mode;
        enum phy_fia tc_phy_fia;
        u8 tc_phy_fia_idx;
 

diff --git a/sys/dev/pci/drm/i915/display/intel_tc.c b/sys/dev/pci/drm/i915/display/intel_tc.c
index 6a39608..04450f1 100644 (file)
--- a/sys/dev/pci/drm/i915/display/intel_tc.c
+++ b/sys/dev/pci/drm/i915/display/intel_tc.c
@@ -5,6 +5,7 @@
 
 #include "i915_drv.h"
 #include "i915_reg.h"
+#include "intel_de.h"
 #include "intel_display.h"
 #include "intel_display_power_map.h"
 #include "intel_display_types.h"
@@ -116,6 +117,24 @@ assert_tc_cold_blocked(struct intel_digital_port *dig_port)
        drm_WARN_ON(&i915->drm, !enabled);
 }
 
+static enum intel_display_power_domain
+tc_port_power_domain(struct intel_digital_port *dig_port)
+{
+       struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
+       enum tc_port tc_port = intel_port_to_tc(i915, dig_port->base.port);
+
+       return POWER_DOMAIN_PORT_DDI_LANES_TC1 + tc_port - TC_PORT_1;
+}
+
+static void
+assert_tc_port_power_enabled(struct intel_digital_port *dig_port)
+{
+       struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
+
+       drm_WARN_ON(&i915->drm,
+                   !intel_display_power_is_enabled(i915, tc_port_power_domain(dig_port)));
+}
+
 u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port)
 {
        struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
@@ -693,6 +712,16 @@ static void __intel_tc_port_put_link(struct intel_digital_port *dig_port)
        dig_port->tc_link_refcount--;
 }
 
+static bool tc_port_is_enabled(struct intel_digital_port *dig_port)
+{
+       struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
+
+       assert_tc_port_power_enabled(dig_port);
+
+       return intel_de_read(i915, DDI_BUF_CTL(dig_port->base.port)) &
+              DDI_BUF_CTL_ENABLE;
+}
+
 /**
  * intel_tc_port_init_mode: Read out HW state and init the given port's TypeC mode
  * @dig_port: digital port
@@ -715,9 +744,23 @@ void intel_tc_port_init_mode(struct intel_digital_port *dig_port)
        tc_cold_wref = tc_cold_block(dig_port, &domain);
 
        dig_port->tc_mode = intel_tc_port_get_current_mode(dig_port);
+       /*
+        * Save the initial mode for the state check in
+        * intel_tc_port_sanitize_mode().
+        */
+       dig_port->tc_init_mode = dig_port->tc_mode;
+       dig_port->tc_lock_wakeref = tc_cold_block(dig_port, &dig_port->tc_lock_power_domain);
+
+       /*
+        * The PHY needs to be connected for AUX to work during HW readout and
+        * MST topology resume, but the PHY mode can only be changed if the
+        * port is disabled.
+        */
+       if (!tc_port_is_enabled(dig_port))
+               intel_tc_port_update_mode(dig_port, 1, false);
+
        /* Prevent changing dig_port->tc_mode until intel_tc_port_sanitize_mode() is called. */
        __intel_tc_port_get_link(dig_port);
-       dig_port->tc_lock_wakeref = tc_cold_block(dig_port, &dig_port->tc_lock_power_domain);
 
        tc_cold_unblock(dig_port, domain, tc_cold_wref);
 
@@ -764,11 +807,11 @@ void intel_tc_port_sanitize_mode(struct intel_digital_port *dig_port)
                 * we'll just switch to disconnected mode from it here without
                 * a note.
                 */
-               if (dig_port->tc_mode != TC_PORT_TBT_ALT)
+               if (dig_port->tc_init_mode != TC_PORT_TBT_ALT)
                        drm_dbg_kms(&i915->drm,
                                    "Port %s: PHY left in %s mode on disabled port, disconnecting it\n",
                                    dig_port->tc_port_name,
-                                   tc_port_mode_name(dig_port->tc_mode));
+                                   tc_port_mode_name(dig_port->tc_init_mode));
                icl_tc_phy_disconnect(dig_port);
                __intel_tc_port_put_link(dig_port);