drm/i915/dp: Recheck link state after modeset

Recheck the link state after a passing link training, with a 2 sec delay
to account for cases where the link goes bad following the link training
and the sink doesn't report this via an HPD IRQ.

The delayed work added here will be also used by a later patch after a
failed link training to try to retrain the link with unchanged link
params before reducing the link params.

v2: Don't flush an uninitialized delayed work (on HDMI-only DDI ports).
v3:
- Move the helpers to a new intel_encoder.c file, rename them
  accordingly. (Ville)
- Add the work to intel_encoder instead of intel_digital_port.
- Call the encoder specific link check function via an encoder hook.
- Flush the link check work during encoder destroy from
  intel_dp_encoder_flush_work().
- Flush the link check work during encoder suspend as well.
v4: Call intel_encoder_link_check_init() with a valid encoder pointer.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240610181428.2955658-1-imre.deak@intel.com

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
index 40fee8380a81..4d279cadf7e2 100644
--- a/drivers/gpu/drm/i915/display/g4x_dp.c
+++ b/drivers/gpu/drm/i915/display/g4x_dp.c
@@ -20,6 +20,7 @@
 #include "intel_dp_aux.h"
 #include "intel_dp_link_training.h"
 #include "intel_dpio_phy.h"
+#include "intel_encoder.h"
 #include "intel_fifo_underrun.h"
 #include "intel_hdmi.h"
 #include "intel_hotplug.h"
@@ -1239,6 +1240,15 @@ static bool ilk_digital_port_connected(struct intel_encoder *encoder)
 	return intel_de_read(dev_priv, DEISR) & bit;
 }
 
+static void g4x_dp_suspend_complete(struct intel_encoder *encoder)
+{
+	/*
+	 * TODO: Move this to intel_dp_encoder_suspend(),
+	 * once modeset locking around that is removed.
+	 */
+	intel_encoder_link_check_flush_work(encoder);
+}
+
 static void intel_dp_encoder_destroy(struct drm_encoder *encoder)
 {
 	intel_dp_encoder_flush_work(encoder);
@@ -1325,6 +1335,8 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
 			     "DP %c", port_name(port)))
 		goto err_encoder_init;
 
+	intel_encoder_link_check_init(intel_encoder, intel_dp_link_check);
+
 	intel_encoder->hotplug = intel_dp_hotplug;
 	intel_encoder->compute_config = intel_dp_compute_config;
 	intel_encoder->get_hw_state = intel_dp_get_hw_state;
@@ -1333,6 +1345,7 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
 	intel_encoder->initial_fastset_check = intel_dp_initial_fastset_check;
 	intel_encoder->update_pipe = intel_backlight_update;
 	intel_encoder->suspend = intel_dp_encoder_suspend;
+	intel_encoder->suspend_complete = g4x_dp_suspend_complete;
 	intel_encoder->shutdown = intel_dp_encoder_shutdown;
 	if (IS_CHERRYVIEW(dev_priv)) {
 		intel_encoder->pre_pll_enable = chv_dp_pre_pll_enable;