diff mbox series

[CI,v5,15/18] drm/i915/display: Helpers for VRR vblank min and max start

Message ID 20210122232647.22688-15-manasi.d.navare@intel.com (mailing list archive)
State New, archived
Headers show
Series [CI,v5,01/18] drm/i915/display/vrr: Create VRR file and add VRR capability check | expand

Commit Message

Navare, Manasi Jan. 22, 2021, 11:26 p.m. UTC
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

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()

v2:
* Remove TODO and adjust extra scanline const (Manasi)

Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 36 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vrr.h |  2 ++
 2 files changed, 38 insertions(+)

Comments

Ville Syrjala Jan. 25, 2021, 11:42 a.m. UTC | #1
On Fri, Jan 22, 2021 at 03:26:44PM -0800, Manasi Navare wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> 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()
> 
> v2:
> * Remove TODO and adjust extra scanline const (Manasi)
> 
> Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
> ---
>  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 c71254563a10..49ff5add90e0 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.

"1-4" now

> + */
> +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);
> +
> +	/* The hw imposes the extra scanline before frame start */
> +	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
> +}
> +
> +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
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index c71254563a10..49ff5add90e0 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);
+
+	/* The hw imposes the extra scanline before frame start */
+	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
+}
+
+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__ */