From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
With VRR the earliest the registers can get latched are at
flipline decision boundary, calculate that as vrr_vmin_vblank_start()
and the latest the regsiters can get latched are vmax decision boundary
calculate that as vrr_vmax_vblank_start()
Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_vrr.c | 36 ++++++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_vrr.h | 2 ++
2 files changed, 38 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 5dc6d578760a..9a18c36e4a9a 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -45,6 +45,42 @@ intel_vrr_check_modeset(struct intel_atomic_state *state)
}
}
+/*
+ * Without VRR registers get latched at:
+ * vblank_start
+ *
+ * With VRR the earliest registers can get latched is:
+ * intel_vrr_vmin_vblank_start(), which if we want to maintain
+ * the correct min vtotal is >=vblank_start+1
+ *
+ * The latest point registers can get latched is the vmax decision boundary:
+ * intel_vrr_vmax_vblank_start()
+ *
+ * Between those two points the vblank exit starts (and hence registers get
+ * latched) ASAP after a push is sent.
+ *
+ * framestart_delay is programmable 0-3.
+ */
+static int intel_vrr_vblank_exit_length(const struct intel_crtc_state *crtc_state)
+{
+ struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+ struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+
+ /* TODO: Not sure why the hw imposes the extra scanline?, also check on TGL */
+ return crtc_state->vrr.pipeline_full + i915->framestart_delay + 2;
+}
+
+int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state)
+{
+ /* Min vblank actually determined by flipline that is always >=vmin+1 */
+ return crtc_state->vrr.vmin + 1 - intel_vrr_vblank_exit_length(crtc_state);
+}
+
+int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state)
+{
+ return crtc_state->vrr.vmax - intel_vrr_vblank_exit_length(crtc_state);
+}
+
void
intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
index 7610051edad2..d8b6b45557ca 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.h
+++ b/drivers/gpu/drm/i915/display/intel_vrr.h
@@ -27,5 +27,7 @@ void intel_vrr_send_push(const struct intel_crtc_state *crtc_state);
void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state);
void intel_vrr_get_config(struct intel_crtc *crtc,
struct intel_crtc_state *crtc_state);
+int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state);
+int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state);
#endif /* __INTEL_VRR_H__ */
--
2.19.1
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