On some Cherry Trail devices, DisplayPort over Type-C is supported through a USB-PD microcontroller (e.g. a fusb302) + a mux to switch the superspeed datalines between USB-3 and DP (e.g. a pi3usb30532). The kernel in this case does the PD/alt-mode negotiation itself, rather then everything being handled in firmware.
So the kernel itself picks an alt-mode, tells the Type-C "dongle" to switch to DP mode and sets the mux accordingly. In this setup the HPD pin is not connected, so the i915 driver needs to respond to a software event and scan the DP port for changes manually.
This commit adds support for this. Together with the recent addition of DP alt-mode support to the Type-C subsystem this makes DP over Type-C work on these devices.
Signed-off-by: Hans de Goede hdegoede@redhat.com --- drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 64a73b3ced94..1029720cc945 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5846,6 +5846,18 @@ static int intel_dp_connector_atomic_check(struct drm_connector *conn, return intel_modeset_synced_crtcs(state, conn); }
+static void intel_dp_oob_hotplug_event(struct drm_connector *connector, + struct drm_connector_oob_hotplug_event_data *data) +{ + struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector)); + struct drm_i915_private *i915 = to_i915(connector->dev); + + spin_lock_irq(&i915->irq_lock); + i915->hotplug.event_bits |= BIT(encoder->hpd_pin); + spin_unlock_irq(&i915->irq_lock); + queue_delayed_work(system_wq, &i915->hotplug.hotplug_work, 0); +} + static const struct drm_connector_funcs intel_dp_connector_funcs = { .force = intel_dp_force, .fill_modes = drm_helper_probe_single_connector_modes, @@ -5856,6 +5868,7 @@ static const struct drm_connector_funcs intel_dp_connector_funcs = { .destroy = intel_connector_destroy, .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, .atomic_duplicate_state = intel_digital_connector_duplicate_state, + .oob_hotplug_event = intel_dp_oob_hotplug_event, };
static const struct drm_connector_helper_funcs intel_dp_connector_helper_funcs = {