drm/i915/fbc: Start using flip nuke

The hardware automagically nukes the cfb on flip. We can use
that whenever the plane/crtc configuration doesn't change too
much. Let's hook that up.

We'll need this for glk+ since we need to introduce an extra
vblank wait after FBC disable. As we're currently disabling
FBC around all plane updates we'd slow them down by an extra
frame. Not a great user experience when your fps is always
capped at vrefres/2. With flip nuke we don't need the extra
vblank wait.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191127201222.16669-12-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
index 3ade7e67573a83bc22be30ebeae9adf80376f7b0..c6ab5a0518832a7ba1e9911f773e233640d74ced 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -68,7 +68,7 @@ static unsigned int get_crtc_fence_y_offset(struct intel_fbc *fbc)
  * write to the PLANE_SIZE register. For BDW-, the hardware looks at the value
  * we wrote to PIPESRC.
  */
-static void intel_fbc_get_plane_source_size(struct intel_fbc_state_cache *cache,
+static void intel_fbc_get_plane_source_size(const struct intel_fbc_state_cache *cache,
                                            int *width, int *height)
 {
        if (width)
@@ -78,7 +78,7 @@ static void intel_fbc_get_plane_source_size(struct intel_fbc_state_cache *cache,
 }
 
 static int intel_fbc_calculate_cfb_size(struct drm_i915_private *dev_priv,
-                                       struct intel_fbc_state_cache *cache)
+                                       const struct intel_fbc_state_cache *cache)
 {
        int lines;
 
@@ -827,6 +827,38 @@ static void intel_fbc_get_reg_params(struct intel_crtc *crtc,
        params->plane_visible = cache->plane.visible;
 }
 
+static bool intel_fbc_can_flip_nuke(const struct intel_crtc_state *crtc_state)
+{
+       struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+       struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+       const struct intel_fbc *fbc = &dev_priv->fbc;
+       const struct intel_fbc_state_cache *cache = &fbc->state_cache;
+       const struct intel_fbc_reg_params *params = &fbc->params;
+
+       if (drm_atomic_crtc_needs_modeset(&crtc_state->uapi))
+               return false;
+
+       if (!params->plane_visible)
+               return false;
+
+       if (!intel_fbc_can_activate(crtc))
+               return false;
+
+       if (params->fb.format != cache->fb.format)
+               return false;
+
+       if (params->fb.stride != cache->fb.stride)
+               return false;
+
+       if (params->cfb_size != intel_fbc_calculate_cfb_size(dev_priv, cache))
+               return false;
+
+       if (params->gen9_wa_cfb_stride != cache->gen9_wa_cfb_stride)
+               return false;
+
+       return true;
+}
+
 void intel_fbc_pre_update(struct intel_crtc *crtc,
                          const struct intel_crtc_state *crtc_state,
                          const struct intel_plane_state *plane_state)
@@ -846,7 +878,8 @@ void intel_fbc_pre_update(struct intel_crtc *crtc,
        intel_fbc_update_state_cache(crtc, crtc_state, plane_state);
        fbc->flip_pending = true;
 
-       intel_fbc_deactivate(dev_priv, reason);
+       if (!intel_fbc_can_flip_nuke(crtc_state))
+               intel_fbc_deactivate(dev_priv, reason);
 unlock:
        mutex_unlock(&fbc->lock);
 }
@@ -885,7 +918,6 @@ static void __intel_fbc_post_update(struct intel_crtc *crtc)
                return;
 
        fbc->flip_pending = false;
-       WARN_ON(fbc->active);
 
        if (!i915_modparams.enable_fbc) {
                intel_fbc_deactivate(dev_priv, "disabled at runtime per module param");
@@ -899,10 +931,9 @@ static void __intel_fbc_post_update(struct intel_crtc *crtc)
        if (!intel_fbc_can_activate(crtc))
                return;
 
-       if (!fbc->busy_bits) {
-               intel_fbc_deactivate(dev_priv, "FBC enabled (active or scheduled)");
+       if (!fbc->busy_bits)
                intel_fbc_hw_activate(dev_priv);
-       } else
+       else
                intel_fbc_deactivate(dev_priv, "frontbuffer write");
 }
 
@@ -1061,10 +1092,7 @@ void intel_fbc_enable(struct intel_crtc *crtc,
        mutex_lock(&fbc->lock);
 
        if (fbc->crtc) {
-               if (fbc->crtc == crtc) {
-                       WARN_ON(!crtc_state->enable_fbc);
-                       WARN_ON(fbc->active);
-               }
+               WARN_ON(fbc->crtc == crtc && !crtc_state->enable_fbc);
                goto out;
        }