From: Derek Foreman <[email protected]>

Add VTEM EMP generation to enable variable refresh rate signalling over
HDMI.

These infoframes are only generated if the sink supports VRR.

Signed-off-by: Derek Foreman <[email protected]>
Signed-off-by: Nicolas Frattaroli <[email protected]>
---
 drivers/gpu/drm/display/drm_hdmi_state_helper.c | 60 +++++++++++++++++++++++++
 include/drm/drm_connector.h                     |  5 +++
 2 files changed, 65 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c 
b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index d55548399687..33d0c9491643 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -853,6 +853,56 @@ static int hdmi_generate_hdmi_vendor_infoframe(const 
struct drm_connector *conne
        return 0;
 }
 
+static int hdmi_generate_emp_infoframe_vtem(const struct drm_connector 
*connector,
+                                           struct drm_connector_state 
*conn_state)
+{
+       const struct drm_display_info *info = &connector->display_info;
+       const struct drm_crtc_state *crtc_state =
+               drm_atomic_get_crtc_state(conn_state->state, conn_state->crtc);
+       struct drm_connector_hdmi_infoframe *infoframe =
+               &conn_state->hdmi.infoframes.vtem;
+       struct hdmi_emp_infoframe_vtem *vtem =
+               &infoframe->data.vtem;
+       const struct drm_crtc_vrr_state *vrr = &crtc_state->vrr_state;
+       int vfront;
+
+       infoframe->set = false;
+
+       if (!connector->hdmi.funcs->vtem.write_infoframe)
+               return 0;
+
+       if (!info->hdmi.vrr_capable)
+               return 0;
+
+       hdmi_emp_infoframe_vtem_init(vtem);
+       if (!crtc_state->vrr_enabled || vrr->vic) {
+               vtem->base_refresh_rate = 0;
+               vtem->base_vfront = 0;
+       } else {
+               vtem->base_refresh_rate = drm_mode_vrefresh(&crtc_state->mode);
+               vfront = crtc_state->adjusted_mode.crtc_vsync_start -
+                        crtc_state->adjusted_mode.crtc_vdisplay;
+               if (vfront > U8_MAX || vfront < 0)
+                       return -EINVAL;
+
+               vtem->base_vfront = vfront;
+       }
+       vtem->fva_factor_m1 = 0;
+       infoframe->set = true;
+
+       if (!crtc_state->vrr_enabled) {
+               vtem->m_const = false;
+               vtem->game_vrr_en = false;
+               return 0;
+       }
+
+       vtem->game_vrr_en = true;
+
+       vtem->m_const = !vrr->dynamic;
+
+       return 0;
+}
+
 static int
 hdmi_generate_infoframes(const struct drm_connector *connector,
                         struct drm_connector_state *conn_state)
@@ -884,6 +934,10 @@ hdmi_generate_infoframes(const struct drm_connector 
*connector,
        if (ret)
                return ret;
 
+       ret = hdmi_generate_emp_infoframe_vtem(connector, conn_state);
+       if (ret)
+               return ret;
+
        return 0;
 }
 
@@ -1494,6 +1548,12 @@ int 
drm_atomic_helper_connector_hdmi_update_infoframes(struct drm_connector *con
                        goto out;
        }
 
+       if (info->hdmi.vrr_capable)
+               ret = write_or_clear_infoframe(connector,
+                                       &funcs->vtem, "VTEM",
+                                       &old_conn_state->hdmi.infoframes.vtem,
+                                       &new_conn_state->hdmi.infoframes.vtem);
+
 out:
        mutex_unlock(&connector->hdmi.infoframes.lock);
        return ret;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index e561a444515f..6e431eb81705 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1180,6 +1180,11 @@ struct drm_connector_hdmi_state {
                 * matching our state.
                 */
                struct drm_connector_hdmi_infoframe hdmi;
+
+               /**
+                * @vtem: VTEM EMP infoframes structure matching our state.
+                */
+               struct drm_connector_hdmi_infoframe vtem;
        } infoframes;
 
        /**

-- 
2.55.0

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