drm/i915: Handle failure to kick out a conflicting fb driver

commit f96de58f upstream.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/gpu/drm/i915/i915_dma.c

@@ -1425,15 +1425,16 @@ void i915_master_destroy(struct drm_device *dev, struct drm_master *master)
 }
 
 #if IS_ENABLED(CONFIG_FB)
-static void i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
+static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
 {
 	struct apertures_struct *ap;
 	struct pci_dev *pdev = dev_priv->dev->pdev;
 	bool primary;
+	int ret;
 
 	ap = alloc_apertures(1);
 	if (!ap)
-		return;
+		return -ENOMEM;
 
 	ap->ranges[0].base = dev_priv->gtt.mappable_base;
 	ap->ranges[0].size = dev_priv->gtt.mappable_end;
@@ -1441,13 +1442,16 @@ static void i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
 	primary =
 		pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
 
-	remove_conflicting_framebuffers(ap, "inteldrmfb", primary);
+	ret = remove_conflicting_framebuffers(ap, "inteldrmfb", primary);
 
 	kfree(ap);
+
+	return ret;
 }
 #else
-static void i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
+static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
 {
+	return 0;
 }
 #endif
 
@@ -1664,7 +1668,11 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 			goto out_gtt;
 		}
 
-		i915_kick_out_firmware_fb(dev_priv);
+		ret = i915_kick_out_firmware_fb(dev_priv);
+		if (ret) {
+			DRM_ERROR("failed to remove conflicting framebuffer drivers\n");
+			goto out_gtt;
+		}
 	}
 
 	pci_set_master(dev->pdev);