drm: Protect fb_defio in drivers with CONFIG_KMS_FBDEV_EMULATION

For reasons that entirely elude me fb.h exposes all the structures,
even when it is not enabled. Except for special stuff like fb_defio.

Which means all the drivers which haven't yet switched over to the
defio support in the helpers and still roll their own, will fail
to compile when fbdev emulation is disabled. Protect just those
bits, as a gnarly reminder that conversion to the core defio helpers
would be good.

Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1470847958-28465-6-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/qxl/qxl_fb.c

@@ -72,10 +72,12 @@ static void qxl_fb_image_init(struct qxl_fb_image *qxl_fb_image,
 	}
 }
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 static struct fb_deferred_io qxl_defio = {
 	.delay		= QXL_DIRTY_DELAY,
 	.deferred_io	= drm_fb_helper_deferred_io,
 };
+#endif
 
 static struct fb_ops qxlfb_ops = {
 	.owner = THIS_MODULE,
@@ -312,8 +314,10 @@ static int qxlfb_create(struct qxl_fbdev *qfbdev,
 		goto out_destroy_fbi;
 	}
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	info->fbdefio = &qxl_defio;
 	fb_deferred_io_init(info);
+#endif
 
 	qdev->fbdev_info = info;
 	qdev->fbdev_qfb = &qfbdev->qfb;

drivers/gpu/drm/udl/udl_fb.c

@@ -203,6 +203,7 @@ static int udl_fb_open(struct fb_info *info, int user)
 
 	ufbdev->fb_count++;
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	if (fb_defio && (info->fbdefio == NULL)) {
 		/* enable defio at last moment if not disabled by client */
 
@@ -218,6 +219,7 @@ static int udl_fb_open(struct fb_info *info, int user)
 		info->fbdefio = fbdefio;
 		fb_deferred_io_init(info);
 	}
+#endif
 
 	pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
 		  info->node, user, info, ufbdev->fb_count);
@@ -235,12 +237,14 @@ static int udl_fb_release(struct fb_info *info, int user)
 
 	ufbdev->fb_count--;
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	if ((ufbdev->fb_count == 0) && (info->fbdefio)) {
 		fb_deferred_io_cleanup(info);
 		kfree(info->fbdefio);
 		info->fbdefio = NULL;
 		info->fbops->fb_mmap = udl_fb_mmap;
 	}
+#endif
 
 	pr_warn("released /dev/fb%d user=%d count=%d\n",
 		info->node, user, ufbdev->fb_count);