drm/i915/fbc: Remove intel_fbc_global_disable()

By the time intel_fbc_global_disable() gets called during driver
teardown we should have already disabled all the crtcs, so
no way FBC should be enabled at this point.

And I have no idea what the other user (i915_restore_display())
is even trying to achieve.

So let's just throw intel_fbc_global_disable() into the bin.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220315140001.1172-6-ville.syrjala@linux.intel.comReviewed-by: Mika Kahola <mika.kahola@intel.com>

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

@@ -10568,8 +10568,6 @@ void intel_modeset_driver_remove_noirq(struct drm_i915_private *i915)
 
 	intel_unregister_dsm_handler();
 
-	intel_fbc_global_disable(i915);
-
 	/* flush any delayed tasks or pending work */
 	flush_scheduled_work();
 

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

@@ -1517,25 +1517,6 @@ void intel_fbc_update(struct intel_atomic_state *state,
 	}
 }
 
-/**
- * intel_fbc_global_disable - globally disable FBC
- * @i915: i915 device instance
- *
- * This function disables FBC regardless of which CRTC is associated with it.
- */
-void intel_fbc_global_disable(struct drm_i915_private *i915)
-{
-	struct intel_fbc *fbc;
-	enum intel_fbc_id fbc_id;
-
-	for_each_intel_fbc(i915, fbc, fbc_id) {
-		mutex_lock(&fbc->lock);
-		if (fbc->state.plane)
-			__intel_fbc_disable(fbc);
-		mutex_unlock(&fbc->lock);
-	}
-}
-
 static void intel_fbc_underrun_work_fn(struct work_struct *work)
 {
 	struct intel_fbc *fbc = container_of(work, typeof(*fbc), underrun_work);

drivers/gpu/drm/i915/display/intel_fbc.h

@@ -33,7 +33,6 @@ void intel_fbc_cleanup(struct drm_i915_private *dev_priv);
 void intel_fbc_update(struct intel_atomic_state *state,
 		      struct intel_crtc *crtc);
 void intel_fbc_disable(struct intel_crtc *crtc);
-void intel_fbc_global_disable(struct drm_i915_private *dev_priv);
 void intel_fbc_invalidate(struct drm_i915_private *dev_priv,
 			  unsigned int frontbuffer_bits,
 			  enum fb_op_origin origin);

drivers/gpu/drm/i915/i915_suspend.c

@@ -25,7 +25,6 @@
  */
 
 #include "display/intel_de.h"
-#include "display/intel_fbc.h"
 #include "display/intel_gmbus.h"
 #include "display/intel_vga.h"
 
@@ -119,9 +118,6 @@ void i915_restore_display(struct drm_i915_private *dev_priv)
 	if (GRAPHICS_VER(dev_priv) <= 4)
 		intel_de_write(dev_priv, DSPARB, dev_priv->regfile.saveDSPARB);
 
-	/* only restore FBC info on the platform that supports FBC*/
-	intel_fbc_global_disable(dev_priv);
-
 	intel_vga_redisable(dev_priv);
 
 	intel_gmbus_reset(dev_priv);