drm/i915: Move PIPE_CHICKEN RMW out from the vblank evade critical section

We don't want any RMWs in the part of the commit that happens
under vblank evasion. Eventually we want to use the DSB to
handle that and it can't read registers at all. Also reads
are just slowing us down needlessly.

Let's move the whole PIPE_CHICKEN stuff out from the critical
section since we don't have anything there that needs to be
syncrhonized with other plane/pipe registers. If we ever need
to add such things then we have to move it back, but without
doing any reads.

TODO: should look into eliminating the RMW anyway...
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220202111616.1579-1-ville.syrjala@linux.intel.comReviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -7878,9 +7878,6 @@ static void intel_pipe_fastset(const struct intel_crtc_state *old_crtc_state,
 	if (DISPLAY_VER(dev_priv) >= 9 ||
 	    IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
 		hsw_set_linetime_wm(new_crtc_state);
-
-	if (DISPLAY_VER(dev_priv) >= 11)
-		icl_set_pipe_chicken(new_crtc_state);
 }
 
 static void commit_pipe_pre_planes(struct intel_atomic_state *state,
@@ -7955,6 +7952,7 @@ static void intel_enable_crtc(struct intel_atomic_state *state,
 static void intel_update_crtc(struct intel_atomic_state *state,
 			      struct intel_crtc *crtc)
 {
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
 	const struct intel_crtc_state *old_crtc_state =
 		intel_atomic_get_old_crtc_state(state, crtc);
 	struct intel_crtc_state *new_crtc_state =
@@ -7971,6 +7969,10 @@ static void intel_update_crtc(struct intel_atomic_state *state,
 
 		if (new_crtc_state->update_pipe)
 			intel_encoders_update_pipe(state, crtc);
+
+		if (DISPLAY_VER(i915) >= 11 &&
+		    new_crtc_state->update_pipe)
+			icl_set_pipe_chicken(new_crtc_state);
 	}
 
 	intel_fbc_update(state, crtc);