[PATCH 10/12] drm/i915/flipq: Implement Wa_16018781658 for LNL-A0

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The normal flip queue completion interrupt doesn't work on LNL-A0,
and instead the firmware implements a workaround via the delayed
vblank event handler. Implement said workaround on the driver side
by enabling the appropriate event and handling the result interrupt
vector value in the PIPEDMC irq handler.

Included here just for reference since LNL-A0 is pre-production
and we don't actually care about it anymore.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dmc.c   | 19 ++++++++++++++++++-
 drivers/gpu/drm/i915/display/intel_flipq.c | 12 ++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index 10d1be68df79..cd024254db7b 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -1516,9 +1516,26 @@ void intel_pipedmc_irq_handler(struct intel_display *display, enum pipe pipe)
 	}
 
 	tmp = intel_de_read(display, PIPEDMC_STATUS(pipe)) & PIPEDMC_INT_VECTOR_MASK;
-	if (tmp)
+	/* Wa_16018781658 */
+	if (tmp == PIPEDMC_INT_VECTOR_FLIPQ_PROG_DONE) {
+		spin_lock(&display->drm->event_lock);
+
+		if (crtc->flipq_event) {
+			/*
+			 * Update vblank counter/timestamp in case it
+			 * hasn't been done yet for this frame.
+			 */
+			drm_crtc_accurate_vblank_count(&crtc->base);
+
+			drm_crtc_send_vblank_event(&crtc->base, crtc->flipq_event);
+			crtc->flipq_event = NULL;
+		}
+
+		spin_unlock(&display->drm->event_lock);
+	} else if (tmp) {
 		drm_err(display->drm, "[CRTC:%d:%s]] PIPEDMC interrupt vector 0x%x\n",
 			crtc->base.base.id, crtc->base.name, tmp);
+	}
 }
 
 void intel_pipedmc_enable_event(struct intel_crtc *crtc,
diff --git a/drivers/gpu/drm/i915/display/intel_flipq.c b/drivers/gpu/drm/i915/display/intel_flipq.c
index c4b4ecd44eb2..fdda8d71c182 100644
--- a/drivers/gpu/drm/i915/display/intel_flipq.c
+++ b/drivers/gpu/drm/i915/display/intel_flipq.c
@@ -215,6 +215,14 @@ void intel_flipq_enable(const struct intel_crtc_state *crtc_state)
 
 	intel_pipedmc_enable_event(crtc, PIPEDMC_EVENT_SCANLINE_INRANGE_FQ_TRIGGER);
 
+	/*
+	 * Wa_16018781658
+	 * PIPEDMC_FPQ_CTL2 bit 1 isn't working, firmware implements
+	 * a workaround via the delayed vblank handler.
+	 */
+	if (display->platform.lunarlake && IS_DISPLAY_STEP(display, STEP_A0, STEP_B0))
+		intel_pipedmc_enable_event(crtc, PIPEDMC_EVENT_DELAYED_VBLANK);
+
 	intel_de_write(display, PIPEDMC_FQ_CTRL(crtc->pipe), PIPEDMC_FQ_CTRL_ENABLE);
 }
 
@@ -225,6 +233,10 @@ void intel_flipq_disable(const struct intel_crtc_state *crtc_state)
 
 	intel_de_write(display, PIPEDMC_FQ_CTRL(crtc->pipe), 0);
 
+	/* Wa_16018781658 */
+	if (display->platform.lunarlake && IS_DISPLAY_STEP(display, STEP_A0, STEP_B0))
+		intel_pipedmc_disable_event(crtc, PIPEDMC_EVENT_DELAYED_VBLANK);
+
 	intel_pipedmc_disable_event(crtc, PIPEDMC_EVENT_SCANLINE_INRANGE_FQ_TRIGGER);
 
 	intel_de_write(display, PIPEDMC_SCANLINECMPLOWER(crtc->pipe), 0);
-- 
2.49.0