Merge branch 'staging/drm/fixes' into staging/master

24 files changed, 133 insertions, 78 deletions

diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
index 948cb14c561..9437e11d5df 100644
--- a/drivers/gpu/drm/armada/armada_fbdev.c
+++ b/drivers/gpu/drm/armada/armada_fbdev.c
@@ -131,7 +131,7 @@ static int armada_fb_probe(struct drm_fb_helper *fbh,
 	return ret;
 }
 
-static struct drm_fb_helper_funcs armada_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs armada_fb_helper_funcs = {
 	.gamma_set	= armada_drm_crtc_gamma_set,
 	.gamma_get	= armada_drm_crtc_gamma_get,
 	.fb_probe	= armada_fb_probe,
@@ -149,7 +149,7 @@ int armada_fbdev_init(struct drm_device *dev)
 
 	priv->fbdev = fbh;
 
-	fbh->funcs = &armada_fb_helper_funcs;
+	drm_fb_helper_prepare(dev, fbh, &armada_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(dev, fbh, 1, 1);
 	if (ret) {
diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
index a28640f47c2..cba45c77455 100644
--- a/drivers/gpu/drm/ast/ast_fb.c
+++ b/drivers/gpu/drm/ast/ast_fb.c
@@ -287,7 +287,7 @@ static void ast_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 	*blue = ast_crtc->lut_b[regno] << 8;
 }
 
-static struct drm_fb_helper_funcs ast_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs ast_fb_helper_funcs = {
 	.gamma_set = ast_fb_gamma_set,
 	.gamma_get = ast_fb_gamma_get,
 	.fb_probe = astfb_create,
@@ -328,8 +328,10 @@ int ast_fbdev_init(struct drm_device *dev)
 		return -ENOMEM;
 
 	ast->fbdev = afbdev;
-	afbdev->helper.funcs = &ast_fb_helper_funcs;
 	spin_lock_init(&afbdev->dirty_lock);
+
+	drm_fb_helper_prepare(dev, &afbdev->helper, &ast_fb_helper_funcs);
+
 	ret = drm_fb_helper_init(dev, &afbdev->helper,
 				 1, 1);
 	if (ret) {
diff --git a/drivers/gpu/drm/bochs/bochs_fbdev.c b/drivers/gpu/drm/bochs/bochs_fbdev.c
index 561b8447412..19cf3e9413b 100644
--- a/drivers/gpu/drm/bochs/bochs_fbdev.c
+++ b/drivers/gpu/drm/bochs/bochs_fbdev.c
@@ -179,7 +179,7 @@ void bochs_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 	*blue  = regno;
 }
 
-static struct drm_fb_helper_funcs bochs_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs bochs_fb_helper_funcs = {
 	.gamma_set = bochs_fb_gamma_set,
 	.gamma_get = bochs_fb_gamma_get,
 	.fb_probe = bochsfb_create,
@@ -189,7 +189,8 @@ int bochs_fbdev_init(struct bochs_device *bochs)
 {
 	int ret;
 
-	bochs->fb.helper.funcs = &bochs_fb_helper_funcs;
+	drm_fb_helper_prepare(bochs->dev, &bochs->fb.helper,
+			      &bochs_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(bochs->dev, &bochs->fb.helper,
 				 1, 1);
diff --git a/drivers/gpu/drm/cirrus/cirrus_fbdev.c b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
index 32bbba0a787..2a135f253e2 100644
--- a/drivers/gpu/drm/cirrus/cirrus_fbdev.c
+++ b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
@@ -288,7 +288,7 @@ static int cirrus_fbdev_destroy(struct drm_device *dev,
 	return 0;
 }
 
-static struct drm_fb_helper_funcs cirrus_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs cirrus_fb_helper_funcs = {
 	.gamma_set = cirrus_crtc_fb_gamma_set,
 	.gamma_get = cirrus_crtc_fb_gamma_get,
 	.fb_probe = cirrusfb_create,
@@ -306,9 +306,11 @@ int cirrus_fbdev_init(struct cirrus_device *cdev)
 		return -ENOMEM;
 
 	cdev->mode_info.gfbdev = gfbdev;
-	gfbdev->helper.funcs = &cirrus_fb_helper_funcs;
 	spin_lock_init(&gfbdev->dirty_lock);
 
+	drm_fb_helper_prepare(cdev->dev, &gfbdev->helper,
+			      &cirrus_fb_helper_funcs);
+
 	ret = drm_fb_helper_init(cdev->dev, &gfbdev->helper,
 				 cdev->num_crtc, CIRRUSFB_CONN_LIMIT);
 	if (ret) {
diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
index 61b5a47ad23..acbbd230e08 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -327,7 +327,7 @@ err_drm_gem_cma_free_object:
 	return ret;
 }
 
-static struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
+static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
 	.fb_probe = drm_fbdev_cma_create,
 };
 
@@ -354,9 +354,10 @@ struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	fbdev_cma->fb_helper.funcs = &drm_fb_cma_helper_funcs;
 	helper = &fbdev_cma->fb_helper;
 
+	drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);
+
 	ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
 	if (ret < 0) {
 		dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index e95ed5805f0..a8804bc78a6 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -49,10 +49,11 @@ static LIST_HEAD(kernel_fb_helper_list);
  * helper functions used by many drivers to implement the kernel mode setting
  * interfaces.
  *
- * Initialization is done as a three-step process with drm_fb_helper_init(),
- * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
- * Drivers with fancier requirements than the default behaviour can override the
- * second step with their own code.  Teardown is done with drm_fb_helper_fini().
+ * Initialization is done as a four-step process with drm_fb_helper_prepare(),
+ * drm_fb_helper_init(), drm_fb_helper_single_add_all_connectors() and
+ * drm_fb_helper_initial_config(). Drivers with fancier requirements than the
+ * default behaviour can override the third step with their own code.
+ * Teardown is done with drm_fb_helper_fini().
  *
  * At runtime drivers should restore the fbdev console by calling
  * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
@@ -63,6 +64,19 @@ static LIST_HEAD(kernel_fb_helper_list);
  *
  * All other functions exported by the fb helper library can be used to
  * implement the fbdev driver interface by the driver.
+ *
+ * It is possible, though perhaps somewhat tricky, to implement race-free
+ * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
+ * helper must be called first to initialize the minimum required to make
+ * hotplug detection work. Drivers also need to make sure to properly set up
+ * the dev->mode_config.funcs member. After calling drm_kms_helper_poll_init()
+ * it is safe to enable interrupts and start processing hotplug events. At the
+ * same time, drivers should initialize all modeset objects such as CRTCs,
+ * encoders and connectors. To finish up the fbdev helper initialization, the
+ * drm_fb_helper_init() function is called. To probe for all attached displays
+ * and set up an initial configuration using the detected hardware, drivers
+ * should call drm_fb_helper_single_add_all_connectors() followed by
+ * drm_fb_helper_initial_config().
  */
 
 /**
@@ -502,6 +516,24 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
 }
 
 /**
+ * drm_fb_helper_prepare - setup a drm_fb_helper structure
+ * @dev: DRM device
+ * @helper: driver-allocated fbdev helper structure to set up
+ * @funcs: pointer to structure of functions associate with this helper
+ *
+ * Sets up the bare minimum to make the framebuffer helper usable. This is
+ * useful to implement race-free initialization of the polling helpers.
+ */
+void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
+			   const struct drm_fb_helper_funcs *funcs)
+{
+	INIT_LIST_HEAD(&helper->kernel_fb_list);
+	helper->funcs = funcs;
+	helper->dev = dev;
+}
+EXPORT_SYMBOL(drm_fb_helper_prepare);
+
+/**
  * drm_fb_helper_init - initialize a drm_fb_helper structure
  * @dev: drm device
  * @fb_helper: driver-allocated fbdev helper structure to initialize
@@ -513,8 +545,7 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
  * to allow driver writes more control over the exact init sequence.
  *
- * Drivers must set fb_helper->funcs before calling
- * drm_fb_helper_initial_config().
+ * Drivers must call drm_fb_helper_prepare() before calling this function.
  *
  * RETURNS:
  * Zero if everything went ok, nonzero otherwise.
@@ -529,10 +560,6 @@ int drm_fb_helper_init(struct drm_device *dev,
 	if (!max_conn_count)
 		return -EINVAL;
 
-	fb_helper->dev = dev;
-
-	INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
-
 	fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
 	if (!fb_helper->crtc_info)
 		return -ENOMEM;
@@ -1587,8 +1614,10 @@ EXPORT_SYMBOL(drm_fb_helper_initial_config);
  * either the output polling work or a work item launched from the driver's
  * hotplug interrupt).
  *
- * Note that the driver must ensure that this is only called _after_ the fb has
- * been fully set up, i.e. after the call to drm_fb_helper_initial_config.
+ * Note that drivers may call this even before calling
+ * drm_fb_helper_initial_config but only aftert drm_fb_helper_init. This allows
+ * for a race-free fbcon setup and will make sure that the fbdev emulation will
+ * not miss any hotplug events.
  *
  * RETURNS:
  * 0 on success and a non-zero error code otherwise.
@@ -1598,11 +1627,8 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
 	struct drm_device *dev = fb_helper->dev;
 	u32 max_width, max_height;
 
-	if (!fb_helper->fb)
-		return 0;
-
 	mutex_lock(&fb_helper->dev->mode_config.mutex);
-	if (!drm_fb_helper_is_bound(fb_helper)) {
+	if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) {
 		fb_helper->delayed_hotplug = true;
 		mutex_unlock(&fb_helper->dev->mode_config.mutex);
 		return 0;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index addbf7536da..46443971d51 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -233,7 +233,7 @@ out:
 	return ret;
 }
 
-static struct drm_fb_helper_funcs exynos_drm_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs exynos_drm_fb_helper_funcs = {
 	.fb_probe =	exynos_drm_fbdev_create,
 };
 
@@ -274,7 +274,8 @@ int exynos_drm_fbdev_init(struct drm_device *dev)
 		return -ENOMEM;
 
 	private->fb_helper = helper = &fbdev->drm_fb_helper;
-	helper->funcs = &exynos_drm_fb_helper_funcs;
+
+	drm_fb_helper_prepare(dev, helper, &exynos_drm_fb_helper_funcs);
 
 	num_crtc = dev->mode_config.num_crtc;
 
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index e7fcc148f33..d0dd3bea8aa 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -561,7 +561,7 @@ static int psbfb_probe(struct drm_fb_helper *helper,
 	return psbfb_create(psb_fbdev, sizes);
 }
 
-static struct drm_fb_helper_funcs psb_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs psb_fb_helper_funcs = {
 	.gamma_set = psbfb_gamma_set,
 	.gamma_get = psbfb_gamma_get,
 	.fb_probe = psbfb_probe,
@@ -600,7 +600,8 @@ int psb_fbdev_init(struct drm_device *dev)
 	}
 
 	dev_priv->fbdev = fbdev;
-	fbdev->psb_fb_helper.funcs = &psb_fb_helper_funcs;
+
+	drm_fb_helper_prepare(dev, &fbdev->psb_fb_helper, &psb_fb_helper_funcs);
 
 	drm_fb_helper_init(dev, &fbdev->psb_fb_helper, dev_priv->ops->crtcs,
 							INTELFB_CONN_LIMIT);
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index f3ae6640563..99dd9f2e17e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1375,9 +1375,6 @@ static int i915_load_modeset_init(struct drm_device *dev)
 	 */
 	intel_fbdev_initial_config(dev);
 
-	/* Only enable hotplug handling once the fbdev is fully set up. */
-	dev_priv->enable_hotplug_processing = true;
-
 	drm_kms_helper_poll_init(dev);
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 31e26f0da9b..8d2be3a3535 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -519,7 +519,6 @@ static int i915_drm_freeze(struct drm_device *dev)
 		}
 
 		drm_irq_uninstall(dev);
-		dev_priv->enable_hotplug_processing = false;
 
 		intel_disable_gt_powersave(dev);
 
@@ -649,7 +648,6 @@ static int __i915_drm_thaw(struct drm_device *dev, bool restore_gtt_mappings)
 		 * notifications.
 		 * */
 		intel_hpd_init(dev);
-		dev_priv->enable_hotplug_processing = true;
 		/* Config may have changed between suspend and resume */
 		drm_helper_hpd_irq_event(dev);
 	}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8631fb36b56..fd0ce053f53 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1386,7 +1386,6 @@ struct drm_i915_private {
 	u32 pipestat_irq_mask[I915_MAX_PIPES];
 
 	struct work_struct hotplug_work;
-	bool enable_hotplug_processing;
 	struct {
 		unsigned long hpd_last_jiffies;
 		int hpd_cnt;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 3b9691e915c..6a05213ed14 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1109,10 +1109,6 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	bool changed = false;
 	u32 hpd_event_bits;
 
-	/* HPD irq before everything is fully set up. */
-	if (!dev_priv->enable_hotplug_processing)
-		return;
-
 	mutex_lock(&mode_config->mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index f6f26a339c5..6c8e25f8fca 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -452,7 +452,7 @@ out:
 	return true;
 }
 
-static struct drm_fb_helper_funcs intel_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs intel_fb_helper_funcs = {
 	.initial_config = intel_fb_initial_config,
 	.gamma_set = intel_crtc_fb_gamma_set,
 	.gamma_get = intel_crtc_fb_gamma_get,
@@ -623,7 +623,8 @@ int intel_fbdev_init(struct drm_device *dev)
 	if (ifbdev == NULL)
 		return -ENOMEM;
 
-	ifbdev->helper.funcs = &intel_fb_helper_funcs;
+	drm_fb_helper_prepare(dev, &ifbdev->helper, &intel_fb_helper_funcs);
+
 	if (!intel_fbdev_init_bios(dev, ifbdev))
 		ifbdev->preferred_bpp = 32;
 
diff --git a/drivers/gpu/drm/mgag200/mgag200_fb.c b/drivers/gpu/drm/mgag200/mgag200_fb.c
index 13b7dd83faa..5451dc58eff 100644
--- a/drivers/gpu/drm/mgag200/mgag200_fb.c
+++ b/drivers/gpu/drm/mgag200/mgag200_fb.c
@@ -272,7 +272,7 @@ static int mga_fbdev_destroy(struct drm_device *dev,
 	return 0;
 }
 
-static struct drm_fb_helper_funcs mga_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs mga_fb_helper_funcs = {
 	.gamma_set = mga_crtc_fb_gamma_set,
 	.gamma_get = mga_crtc_fb_gamma_get,
 	.fb_probe = mgag200fb_create,
@@ -293,9 +293,10 @@ int mgag200_fbdev_init(struct mga_device *mdev)
 		return -ENOMEM;
 
 	mdev->mfbdev = mfbdev;
-	mfbdev->helper.funcs = &mga_fb_helper_funcs;
 	spin_lock_init(&mfbdev->dirty_lock);
 
+	drm_fb_helper_prepare(mdev->dev, &mfbdev->helper, &mga_fb_helper_funcs);
+
 	ret = drm_fb_helper_init(mdev->dev, &mfbdev->helper,
 				 mdev->num_crtc, MGAG200FB_CONN_LIMIT);
 	if (ret)
diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index a752ab83b81..c7d6e85a7bf 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -177,7 +177,7 @@ static void msm_crtc_fb_gamma_get(struct drm_crtc *crtc,
 	DBG("fbdev: get gamma");
 }
 
-static struct drm_fb_helper_funcs msm_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs msm_fb_helper_funcs = {
 	.gamma_set = msm_crtc_fb_gamma_set,
 	.gamma_get = msm_crtc_fb_gamma_get,
 	.fb_probe = msm_fbdev_create,
@@ -197,7 +197,7 @@ struct drm_fb_helper *msm_fbdev_init(struct drm_device *dev)
 
 	helper = &fbdev->base;
 
-	helper->funcs = &msm_fb_helper_funcs;
+	drm_fb_helper_prepare(dev, helper, &msm_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(dev, helper,
 			priv->num_crtcs, priv->num_connectors);
diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index 64a42cfd371..afe706a20f9 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -438,7 +438,7 @@ void nouveau_fbcon_gpu_lockup(struct fb_info *info)
 	info->flags |= FBINFO_HWACCEL_DISABLED;
 }
 
-static struct drm_fb_helper_funcs nouveau_fbcon_helper_funcs = {
+static const struct drm_fb_helper_funcs nouveau_fbcon_helper_funcs = {
 	.gamma_set = nouveau_fbcon_gamma_set,
 	.gamma_get = nouveau_fbcon_gamma_get,
 	.fb_probe = nouveau_fbcon_create,
@@ -464,7 +464,8 @@ nouveau_fbcon_init(struct drm_device *dev)
 
 	fbcon->dev = dev;
 	drm->fbcon = fbcon;
-	fbcon->helper.funcs = &nouveau_fbcon_helper_funcs;
+
+	drm_fb_helper_prepare(dev, &fbcon->helper, &nouveau_fbcon_helper_funcs);
 
 	ret = drm_fb_helper_init(dev, &fbcon->helper,
 				 dev->mode_config.num_crtc, 4);
diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
index 1388ca7f87e..8436c6857cd 100644
--- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
+++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
@@ -281,7 +281,7 @@ fail:
 	return ret;
 }
 
-static struct drm_fb_helper_funcs omap_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
 	.fb_probe = omap_fbdev_create,
 };
 
@@ -325,7 +325,7 @@ struct drm_fb_helper *omap_fbdev_init(struct drm_device *dev)
 
 	helper = &fbdev->base;
 
-	helper->funcs = &omap_fb_helper_funcs;
+	drm_fb_helper_prepare(dev, helper, &omap_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(dev, helper,
 			priv->num_crtcs, priv->num_connectors);
diff --git a/drivers/gpu/drm/qxl/qxl_fb.c b/drivers/gpu/drm/qxl/qxl_fb.c
index f437b30ce68..df567888bb1 100644
--- a/drivers/gpu/drm/qxl/qxl_fb.c
+++ b/drivers/gpu/drm/qxl/qxl_fb.c
@@ -660,7 +660,7 @@ static int qxl_fbdev_destroy(struct drm_device *dev, struct qxl_fbdev *qfbdev)
 	return 0;
 }
 
-static struct drm_fb_helper_funcs qxl_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs qxl_fb_helper_funcs = {
 	.fb_probe = qxl_fb_find_or_create_single,
 };
 
@@ -676,9 +676,12 @@ int qxl_fbdev_init(struct qxl_device *qdev)
 
 	qfbdev->qdev = qdev;
 	qdev->mode_info.qfbdev = qfbdev;
-	qfbdev->helper.funcs = &qxl_fb_helper_funcs;
 	spin_lock_init(&qfbdev->delayed_ops_lock);
 	INIT_LIST_HEAD(&qfbdev->delayed_ops);
+
+	drm_fb_helper_prepare(qdev->ddev, &qfbdev->helper,
+			      &qxl_fb_helper_funcs);
+
 	ret = drm_fb_helper_init(qdev->ddev, &qfbdev->helper,
 				 qxl_num_crtc /* num_crtc - QXL supports just 1 */,
 				 QXLFB_CONN_LIMIT);
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index 665ced3b731..db598d71290 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -331,7 +331,7 @@ static int radeon_fbdev_destroy(struct drm_device *dev, struct radeon_fbdev *rfb
 	return 0;
 }
 
-static struct drm_fb_helper_funcs radeon_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs radeon_fb_helper_funcs = {
 	.gamma_set = radeon_crtc_fb_gamma_set,
 	.gamma_get = radeon_crtc_fb_gamma_get,
 	.fb_probe = radeonfb_create,
@@ -353,7 +353,9 @@ int radeon_fbdev_init(struct radeon_device *rdev)
 
 	rfbdev->rdev = rdev;
 	rdev->mode_info.rfbdev = rfbdev;
-	rfbdev->helper.funcs = &radeon_fb_helper_funcs;
+
+	drm_fb_helper_prepare(rdev->ddev, &rfbdev->helper,
+			      &radeon_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(rdev->ddev, &rfbdev->helper,
 				 rdev->num_crtc,
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 09ee77923d6..d492c2f12ca 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -41,6 +41,12 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 
 	drm_mode_config_init(drm);
 
+	err = tegra_drm_fb_prepare(drm);
+	if (err < 0)
+		return err;
+
+	drm_kms_helper_poll_init(drm);
+
 	err = host1x_device_init(device);
 	if (err < 0)
 		return err;
@@ -60,8 +66,6 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 	if (err < 0)
 		return err;
 
-	drm_kms_helper_poll_init(drm);
-
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 784fd5c7744..d100f706d81 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -284,6 +284,7 @@ struct tegra_bo *tegra_fb_get_plane(struct drm_framebuffer *framebuffer,
 				    unsigned int index);
 bool tegra_fb_is_bottom_up(struct drm_framebuffer *framebuffer);
 bool tegra_fb_is_tiled(struct drm_framebuffer *framebuffer);
+int tegra_drm_fb_prepare(struct drm_device *drm);
 int tegra_drm_fb_init(struct drm_device *drm);
 void tegra_drm_fb_exit(struct drm_device *drm);
 #ifdef CONFIG_DRM_TEGRA_FBDEV
diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
index f7fca09d492..70d0e07d353 100644
--- a/drivers/gpu/drm/tegra/fb.c
+++ b/drivers/gpu/drm/tegra/fb.c
@@ -267,18 +267,13 @@ release:
 	return err;
 }
 
-static struct drm_fb_helper_funcs tegra_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs tegra_fb_helper_funcs = {
 	.fb_probe = tegra_fbdev_probe,
 };
 
-static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm,
-					      unsigned int preferred_bpp,
-					      unsigned int num_crtc,
-					      unsigned int max_connectors)
+static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm)
 {
-	struct drm_fb_helper *helper;
 	struct tegra_fbdev *fbdev;
-	int err;
 
 	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
 	if (!fbdev) {
@@ -286,13 +281,23 @@ static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	fbdev->base.funcs = &tegra_fb_helper_funcs;
-	helper = &fbdev->base;
+	drm_fb_helper_prepare(drm, &fbdev->base, &tegra_fb_helper_funcs);
+
+	return fbdev;
+}
+
+static int tegra_fbdev_init(struct tegra_fbdev *fbdev,
+			    unsigned int preferred_bpp,
+			    unsigned int num_crtc,
+			    unsigned int max_connectors)
+{
+	struct drm_device *drm = fbdev->base.dev;
+	int err;
 
 	err = drm_fb_helper_init(drm, &fbdev->base, num_crtc, max_connectors);
 	if (err < 0) {
 		dev_err(drm->dev, "failed to initialize DRM FB helper\n");
-		goto free;
+		return err;
 	}
 
 	err = drm_fb_helper_single_add_all_connectors(&fbdev->base);
@@ -301,21 +306,17 @@ static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm,
 		goto fini;
 	}
 
-	drm_helper_disable_unused_functions(drm);
-
 	err = drm_fb_helper_initial_config(&fbdev->base, preferred_bpp);
 	if (err < 0) {
 		dev_err(drm->dev, "failed to set initial configuration\n");
 		goto fini;
 	}
 
-	return fbdev;
+	return 0;
 
 fini:
 	drm_fb_helper_fini(&fbdev->base);
-free:
-	kfree(fbdev);
-	return ERR_PTR(err);
+	return err;
 }
 
 static void tegra_fbdev_free(struct tegra_fbdev *fbdev)
@@ -369,7 +370,7 @@ static const struct drm_mode_config_funcs tegra_drm_mode_funcs = {
 #endif
 };
 
-int tegra_drm_fb_init(struct drm_device *drm)
+int tegra_drm_fb_prepare(struct drm_device *drm)
 {
 #ifdef CONFIG_DRM_TEGRA_FBDEV
 	struct tegra_drm *tegra = drm->dev_private;
@@ -384,8 +385,7 @@ int tegra_drm_fb_init(struct drm_device *drm)
 	drm->mode_config.funcs = &tegra_drm_mode_funcs;
 
 #ifdef CONFIG_DRM_TEGRA_FBDEV
-	tegra->fbdev = tegra_fbdev_create(drm, 32, drm->mode_config.num_crtc,
-					  drm->mode_config.num_connector);
+	tegra->fbdev = tegra_fbdev_create(drm);
 	if (IS_ERR(tegra->fbdev))
 		return PTR_ERR(tegra->fbdev);
 #endif
@@ -393,6 +393,21 @@ int tegra_drm_fb_init(struct drm_device *drm)
 	return 0;
 }
 
+int tegra_drm_fb_init(struct drm_device *drm)
+{
+#ifdef CONFIG_DRM_TEGRA_FBDEV
+	struct tegra_drm *tegra = drm->dev_private;
+	int err;
+
+	err = tegra_fbdev_init(tegra->fbdev, 32, drm->mode_config.num_crtc,
+			       drm->mode_config.num_connector);
+	if (err < 0)
+		return err;
+#endif
+
+	return 0;
+}
+
 void tegra_drm_fb_exit(struct drm_device *drm)
 {
 #ifdef CONFIG_DRM_TEGRA_FBDEV
diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
index 377176372da..d1da339843c 100644
--- a/drivers/gpu/drm/udl/udl_fb.c
+++ b/drivers/gpu/drm/udl/udl_fb.c
@@ -550,7 +550,7 @@ out:
 	return ret;
 }
 
-static struct drm_fb_helper_funcs udl_fb_helper_funcs = {
+static const struct drm_fb_helper_funcs udl_fb_helper_funcs = {
 	.fb_probe = udlfb_create,
 };
 
@@ -583,7 +583,8 @@ int udl_fbdev_init(struct drm_device *dev)
 		return -ENOMEM;
 
 	udl->fbdev = ufbdev;
-	ufbdev->helper.funcs = &udl_fb_helper_funcs;
+
+	drm_fb_helper_prepare(dev, &ufbdev->helper, &udl_fb_helper_funcs);
 
 	ret = drm_fb_helper_init(dev, &ufbdev->helper,
 				 1, 1);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 6e622f7d481..9b83c66a5f1 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -87,7 +87,7 @@ struct drm_fb_helper {
 	struct drm_fb_helper_crtc *crtc_info;
 	int connector_count;
 	struct drm_fb_helper_connector **connector_info;
-	struct drm_fb_helper_funcs *funcs;
+	const struct drm_fb_helper_funcs *funcs;
 	struct fb_info *fbdev;
 	u32 pseudo_palette[17];
 	struct list_head kernel_fb_list;
@@ -97,6 +97,8 @@ struct drm_fb_helper {
 	bool delayed_hotplug;
 };
 
+void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
+			   const struct drm_fb_helper_funcs *funcs);
 int drm_fb_helper_init(struct drm_device *dev,
 		       struct drm_fb_helper *helper, int crtc_count,
 		       int max_conn);