drm/i915: Fix bw atomic check when switching between SAGV vs. no SAGV

From Ville Syrjala
0726fca0b6cc26a9ee6b0a0ac8984b8be0c62fb8 in linux 5.15.y/5.15.26
ec663bca9128f13eada25cd0446e7fcb5fcdc088 in mainline linux

diff --git a/sys/dev/pci/drm/i915/display/intel_bw.c b/sys/dev/pci/drm/i915/display/intel_bw.c
index 4b94256..7144c76 100644 (file)
--- a/sys/dev/pci/drm/i915/display/intel_bw.c
+++ b/sys/dev/pci/drm/i915/display/intel_bw.c
@@ -681,6 +681,7 @@ int intel_bw_atomic_check(struct intel_atomic_state *state)
        unsigned int max_bw_point = 0, max_bw = 0;
        unsigned int num_qgv_points = dev_priv->max_bw[0].num_qgv_points;
        unsigned int num_psf_gv_points = dev_priv->max_bw[0].num_psf_gv_points;
+       bool changed = false;
        u32 mask = 0;
 
        /* FIXME earlier gens need some checks too */
@@ -724,6 +725,8 @@ int intel_bw_atomic_check(struct intel_atomic_state *state)
                new_bw_state->data_rate[crtc->pipe] = new_data_rate;
                new_bw_state->num_active_planes[crtc->pipe] = new_active_planes;
 
+               changed = true;
+
                drm_dbg_kms(&dev_priv->drm,
                            "pipe %c data rate %u num active planes %u\n",
                            pipe_name(crtc->pipe),
@@ -731,7 +734,19 @@ int intel_bw_atomic_check(struct intel_atomic_state *state)
                            new_bw_state->num_active_planes[crtc->pipe]);
        }
 
-       if (!new_bw_state)
+       old_bw_state = intel_atomic_get_old_bw_state(state);
+       new_bw_state = intel_atomic_get_new_bw_state(state);
+
+       if (new_bw_state &&
+           intel_can_enable_sagv(dev_priv, old_bw_state) !=
+           intel_can_enable_sagv(dev_priv, new_bw_state))
+               changed = true;
+
+       /*
+        * If none of our inputs (data rates, number of active
+        * planes, SAGV yes/no) changed then nothing to do here.
+        */
+       if (!changed)
                return 0;
 
        ret = intel_atomic_lock_global_state(&new_bw_state->base);
@@ -814,7 +829,6 @@ int intel_bw_atomic_check(struct intel_atomic_state *state)
         */
        new_bw_state->qgv_points_mask = ~allowed_points & mask;
 
-       old_bw_state = intel_atomic_get_old_bw_state(state);
        /*
         * If the actual mask had changed we need to make sure that
         * the commits are serialized(in case this is a nomodeset, nonblocking)