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@xxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dp.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index dfa7da928ae5..554090e6ab7d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4571,6 +4571,17 @@ 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 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,
@@ -4581,6 +4592,7 @@ 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 = {
--
2.31.1
