[PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[Thomas Zimmermann]

Move the calls to drm_fb_helper_alloc_info() from drivers into a
single place in fbdev helpers. Allocates struct fb_info for a new
framebuffer device. Then call drm_fb_helper_single_fb_probe() to
create an fbdev screen buffer. Also release the instance on errors
by calling drm_fb_helper_release_info().

Simplifies the code and fixes the error cleanup for some of the
drivers.

Regular release of the struct fb_info instance still happens in
drm_fb_helper_fini() as before.

v2:
- remove error rollback in driver implementations (kernel test robot)
- initialize info in TTM implementation (kernel test robot)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/armada/armada_fbdev.c      | 12 +------
 drivers/gpu/drm/drm_fb_helper.c            | 39 +++++++---------------
 drivers/gpu/drm/drm_fbdev_dma.c            | 12 ++-----
 drivers/gpu/drm/drm_fbdev_shmem.c          | 12 ++-----
 drivers/gpu/drm/drm_fbdev_ttm.c            | 12 ++-----
 drivers/gpu/drm/exynos/exynos_drm_fbdev.c  |  9 +----
 drivers/gpu/drm/gma500/fbdev.c             | 12 +------
 drivers/gpu/drm/i915/display/intel_fbdev.c |  9 +----
 drivers/gpu/drm/msm/msm_fbdev.c            |  9 +----
 drivers/gpu/drm/omapdrm/omap_fbdev.c       |  9 +----
 drivers/gpu/drm/radeon/radeon_fbdev.c      | 13 +-------
 drivers/gpu/drm/tegra/fbdev.c              |  9 +----
 include/drm/drm_fb_helper.h                | 12 -------
 13 files changed, 26 insertions(+), 143 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
index 22e2081bfa04..601b2aad243b 100644
--- a/drivers/gpu/drm/armada/armada_fbdev.c
+++ b/drivers/gpu/drm/armada/armada_fbdev.c
@@ -43,10 +43,10 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
 				    struct drm_fb_helper_surface_size *sizes)
 {
 	struct drm_device *dev = fbh->dev;
+	struct fb_info *info = fbh->info;
 	struct drm_mode_fb_cmd2 mode;
 	struct armada_framebuffer *dfb;
 	struct armada_gem_object *obj;
-	struct fb_info *info;
 	int size, ret;
 	void *ptr;
 
@@ -90,12 +90,6 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
 	if (IS_ERR(dfb))
 		return PTR_ERR(dfb);
 
-	info = drm_fb_helper_alloc_info(fbh);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_fballoc;
-	}
-
 	info->fbops = &armada_fb_ops;
 	info->fix.smem_start = obj->phys_addr;
 	info->fix.smem_len = obj->obj.size;
@@ -111,8 +105,4 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
 		(unsigned long long)obj->phys_addr);
 
 	return 0;
-
- err_fballoc:
-	dfb->fb.funcs->destroy(&dfb->fb);
-	return ret;
 }
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 53e9dc0543de..dd80f5c5feec 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -495,20 +495,7 @@ int drm_fb_helper_init(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_fb_helper_init);
 
-/**
- * drm_fb_helper_alloc_info - allocate fb_info and some of its members
- * @fb_helper: driver-allocated fbdev helper
- *
- * A helper to alloc fb_info and the member cmap. Called by the driver
- * within the struct &drm_driver.fbdev_probe callback function. Drivers do
- * not need to release the allocated fb_info structure themselves, this is
- * automatically done when calling drm_fb_helper_fini().
- *
- * RETURNS:
- * fb_info pointer if things went okay, pointer containing error code
- * otherwise
- */
-struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
+static struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
 {
 	struct device *dev = fb_helper->dev->dev;
 	struct fb_info *info;
@@ -535,17 +522,8 @@ struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
 	framebuffer_release(info);
 	return ERR_PTR(ret);
 }
-EXPORT_SYMBOL(drm_fb_helper_alloc_info);
 
-/**
- * drm_fb_helper_release_info - release fb_info and its members
- * @fb_helper: driver-allocated fbdev helper
- *
- * A helper to release fb_info and the member cmap.  Drivers do not
- * need to release the allocated fb_info structure themselves, this is
- * automatically done when calling drm_fb_helper_fini().
- */
-void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
+static void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
 {
 	struct fb_info *info = fb_helper->info;
 
@@ -558,7 +536,6 @@ void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
 		fb_dealloc_cmap(&info->cmap);
 	framebuffer_release(info);
 }
-EXPORT_SYMBOL(drm_fb_helper_release_info);
 
 /**
  * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
@@ -1809,6 +1786,11 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
 	height = dev->mode_config.max_height;
 
 	drm_client_modeset_probe(&fb_helper->client, width, height);
+
+	info = drm_fb_helper_alloc_info(fb_helper);
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
 	ret = drm_fb_helper_single_fb_probe(fb_helper);
 	if (ret < 0) {
 		if (ret == -EAGAIN) {
@@ -1817,13 +1799,12 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
 		}
 		mutex_unlock(&fb_helper->lock);
 
-		return ret;
+		goto err_drm_fb_helper_release_info;
 	}
 	drm_setup_crtcs_fb(fb_helper);
 
 	fb_helper->deferred_setup = false;
 
-	info = fb_helper->info;
 	info->var.pixclock = 0;
 
 	/* Need to drop locks to avoid recursive deadlock in
@@ -1846,6 +1827,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
 	mutex_unlock(&kernel_fb_helper_lock);
 
 	return 0;
+
+err_drm_fb_helper_release_info:
+	drm_fb_helper_release_info(fb_helper);
+	return ret;
 }
 
 /**
diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c
index c6196293e424..442d964039b7 100644
--- a/drivers/gpu/drm/drm_fbdev_dma.c
+++ b/drivers/gpu/drm/drm_fbdev_dma.c
@@ -268,9 +268,9 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 {
 	struct drm_client_dev *client = &fb_helper->client;
 	struct drm_device *dev = fb_helper->dev;
+	struct fb_info *info = fb_helper->info;
 	struct drm_client_buffer *buffer;
 	struct drm_framebuffer *fb;
-	struct fb_info *info;
 	u32 format;
 	struct iosys_map map;
 	int ret;
@@ -300,12 +300,6 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	fb_helper->buffer = buffer;
 	fb_helper->fb = fb;
 
-	info = drm_fb_helper_alloc_info(fb_helper);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_drm_client_buffer_vunmap;
-	}
-
 	drm_fb_helper_fill_info(info, fb_helper, sizes);
 
 	if (fb->funcs->dirty)
@@ -313,12 +307,10 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	else
 		ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
 	if (ret)
-		goto err_drm_fb_helper_release_info;
+		goto err_drm_client_buffer_vunmap;
 
 	return 0;
 
-err_drm_fb_helper_release_info:
-	drm_fb_helper_release_info(fb_helper);
 err_drm_client_buffer_vunmap:
 	fb_helper->fb = NULL;
 	fb_helper->buffer = NULL;
diff --git a/drivers/gpu/drm/drm_fbdev_shmem.c b/drivers/gpu/drm/drm_fbdev_shmem.c
index 51573058df6f..2190e2230b83 100644
--- a/drivers/gpu/drm/drm_fbdev_shmem.c
+++ b/drivers/gpu/drm/drm_fbdev_shmem.c
@@ -134,10 +134,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 {
 	struct drm_client_dev *client = &fb_helper->client;
 	struct drm_device *dev = fb_helper->dev;
+	struct fb_info *info = fb_helper->info;
 	struct drm_client_buffer *buffer;
 	struct drm_gem_shmem_object *shmem;
 	struct drm_framebuffer *fb;
-	struct fb_info *info;
 	u32 format;
 	struct iosys_map map;
 	int ret;
@@ -167,12 +167,6 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	fb_helper->buffer = buffer;
 	fb_helper->fb = fb;
 
-	info = drm_fb_helper_alloc_info(fb_helper);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_drm_client_buffer_vunmap;
-	}
-
 	drm_fb_helper_fill_info(info, fb_helper, sizes);
 
 	info->fbops = &drm_fbdev_shmem_fb_ops;
@@ -193,12 +187,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	info->fbdefio = &fb_helper->fbdefio;
 	ret = fb_deferred_io_init(info);
 	if (ret)
-		goto err_drm_fb_helper_release_info;
+		goto err_drm_client_buffer_vunmap;
 
 	return 0;
 
-err_drm_fb_helper_release_info:
-	drm_fb_helper_release_info(fb_helper);
 err_drm_client_buffer_vunmap:
 	fb_helper->fb = NULL;
 	fb_helper->buffer = NULL;
diff --git a/drivers/gpu/drm/drm_fbdev_ttm.c b/drivers/gpu/drm/drm_fbdev_ttm.c
index ccf460fbc1f0..3a06c2b59a8d 100644
--- a/drivers/gpu/drm/drm_fbdev_ttm.c
+++ b/drivers/gpu/drm/drm_fbdev_ttm.c
@@ -174,8 +174,8 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 {
 	struct drm_client_dev *client = &fb_helper->client;
 	struct drm_device *dev = fb_helper->dev;
+	struct fb_info *info = fb_helper->info;
 	struct drm_client_buffer *buffer;
-	struct fb_info *info;
 	size_t screen_size;
 	void *screen_buffer;
 	u32 format;
@@ -203,12 +203,6 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 		goto err_drm_client_framebuffer_delete;
 	}
 
-	info = drm_fb_helper_alloc_info(fb_helper);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_vfree;
-	}
-
 	drm_fb_helper_fill_info(info, fb_helper, sizes);
 
 	info->fbops = &drm_fbdev_ttm_fb_ops;
@@ -225,12 +219,10 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	info->fbdefio = &fb_helper->fbdefio;
 	ret = fb_deferred_io_init(info);
 	if (ret)
-		goto err_drm_fb_helper_release_info;
+		goto err_vfree;
 
 	return 0;
 
-err_drm_fb_helper_release_info:
-	drm_fb_helper_release_info(fb_helper);
 err_vfree:
 	vfree(screen_buffer);
 err_drm_client_framebuffer_delete:
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index a3bd21a827ad..539ce0a87886 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -57,18 +57,11 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 				   struct drm_fb_helper_surface_size *sizes,
 				   struct exynos_drm_gem *exynos_gem)
 {
-	struct fb_info *fbi;
+	struct fb_info *fbi = helper->info;
 	struct drm_framebuffer *fb = helper->fb;
 	unsigned int size = fb->width * fb->height * fb->format->cpp[0];
 	unsigned long offset;
 
-	fbi = drm_fb_helper_alloc_info(helper);
-	if (IS_ERR(fbi)) {
-		DRM_DEV_ERROR(to_dma_dev(helper->dev),
-			      "failed to allocate fb info.\n");
-		return PTR_ERR(fbi);
-	}
-
 	fbi->fbops = &exynos_drm_fb_ops;
 
 	drm_fb_helper_fill_info(fbi, helper, sizes);
diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c
index bc92fa24a1e2..c26926babc2a 100644
--- a/drivers/gpu/drm/gma500/fbdev.c
+++ b/drivers/gpu/drm/gma500/fbdev.c
@@ -108,7 +108,7 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	struct drm_device *dev = fb_helper->dev;
 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
-	struct fb_info *info;
+	struct fb_info *info = fb_helper->info;
 	struct drm_framebuffer *fb;
 	struct drm_mode_fb_cmd2 mode_cmd = { };
 	int size;
@@ -167,12 +167,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	fb_helper->funcs = &psb_fbdev_fb_helper_funcs;
 	fb_helper->fb = fb;
 
-	info = drm_fb_helper_alloc_info(fb_helper);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_drm_framebuffer_unregister_private;
-	}
-
 	info->fbops = &psb_fbdev_fb_ops;
 
 	/* Accessed stolen memory directly */
@@ -196,10 +190,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 
 	return 0;
 
-err_drm_framebuffer_unregister_private:
-	drm_framebuffer_unregister_private(fb);
-	drm_framebuffer_cleanup(fb);
-	kfree(fb);
 err_drm_gem_object_put:
 	drm_gem_object_put(obj);
 	return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
index e5449c41cfa1..9cd03e2adeb2 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -267,8 +267,8 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	struct intel_display *display = to_intel_display(helper->dev);
 	struct intel_fbdev *ifbdev = to_intel_fbdev(helper);
 	struct intel_framebuffer *fb = ifbdev->fb;
+	struct fb_info *info = helper->info;
 	struct ref_tracker *wakeref;
-	struct fb_info *info;
 	struct i915_vma *vma;
 	unsigned long flags = 0;
 	bool prealloc = false;
@@ -318,13 +318,6 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 		goto out_unlock;
 	}
 
-	info = drm_fb_helper_alloc_info(helper);
-	if (IS_ERR(info)) {
-		drm_err(display->drm, "Failed to allocate fb_info (%pe)\n", info);
-		ret = PTR_ERR(info);
-		goto out_unpin;
-	}
-
 	helper->funcs = &intel_fb_helper_funcs;
 	helper->fb = &fb->base;
 
diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index aad6fb77f0de..fd19995b12b5 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -91,9 +91,9 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 {
 	struct drm_device *dev = helper->dev;
 	struct msm_drm_private *priv = dev->dev_private;
+	struct fb_info *fbi = helper->info;
 	struct drm_framebuffer *fb = NULL;
 	struct drm_gem_object *bo;
-	struct fb_info *fbi = NULL;
 	uint64_t paddr;
 	uint32_t format;
 	int ret, pitch;
@@ -126,13 +126,6 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 		goto fail;
 	}
 
-	fbi = drm_fb_helper_alloc_info(helper);
-	if (IS_ERR(fbi)) {
-		DRM_DEV_ERROR(dev->dev, "failed to allocate fb info\n");
-		ret = PTR_ERR(fbi);
-		goto fail;
-	}
-
 	DBG("fbi=%p, dev=%p", fbi, dev);
 
 	helper->funcs = &msm_fbdev_helper_funcs;
diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
index b5df2923d2a6..c4671ab87f9c 100644
--- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
+++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
@@ -153,9 +153,9 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	struct drm_device *dev = helper->dev;
 	struct omap_drm_private *priv = dev->dev_private;
 	struct omap_fbdev *fbdev = priv->fbdev;
+	struct fb_info *fbi = helper->info;
 	struct drm_framebuffer *fb = NULL;
 	union omap_gem_size gsize;
-	struct fb_info *fbi = NULL;
 	struct drm_mode_fb_cmd2 mode_cmd = {0};
 	struct drm_gem_object *bo;
 	dma_addr_t dma_addr;
@@ -224,13 +224,6 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 		goto fail;
 	}
 
-	fbi = drm_fb_helper_alloc_info(helper);
-	if (IS_ERR(fbi)) {
-		dev_err(dev->dev, "failed to allocate fb info\n");
-		ret = PTR_ERR(fbi);
-		goto fail;
-	}
-
 	DBG("fbi=%p, dev=%p", fbi, dev);
 
 	helper->funcs = &omap_fbdev_helper_funcs;
diff --git a/drivers/gpu/drm/radeon/radeon_fbdev.c b/drivers/gpu/drm/radeon/radeon_fbdev.c
index 4df6c9167bf0..1b469b2b4b04 100644
--- a/drivers/gpu/drm/radeon/radeon_fbdev.c
+++ b/drivers/gpu/drm/radeon/radeon_fbdev.c
@@ -204,7 +204,7 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	struct radeon_device *rdev = fb_helper->dev->dev_private;
 	const struct drm_format_info *format_info;
 	struct drm_mode_fb_cmd2 mode_cmd = { };
-	struct fb_info *info;
+	struct fb_info *info = fb_helper->info;
 	struct drm_gem_object *gobj;
 	struct radeon_bo *rbo;
 	struct drm_framebuffer *fb;
@@ -245,13 +245,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 	fb_helper->funcs = &radeon_fbdev_fb_helper_funcs;
 	fb_helper->fb = fb;
 
-	/* okay we have an object now allocate the framebuffer */
-	info = drm_fb_helper_alloc_info(fb_helper);
-	if (IS_ERR(info)) {
-		ret = PTR_ERR(info);
-		goto err_drm_framebuffer_unregister_private;
-	}
-
 	info->fbops = &radeon_fbdev_fb_ops;
 
 	/* radeon resume is fragile and needs a vt switch to help it along */
@@ -277,10 +270,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 
 	return 0;
 
-err_drm_framebuffer_unregister_private:
-	fb_helper->fb = NULL;
-	drm_framebuffer_unregister_private(fb);
-	drm_framebuffer_cleanup(fb);
 err_kfree:
 	kfree(fb);
 err_radeon_fbdev_destroy_pinned_object:
diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
index 91aece6f34e0..8f40882aa76e 100644
--- a/drivers/gpu/drm/tegra/fbdev.c
+++ b/drivers/gpu/drm/tegra/fbdev.c
@@ -73,10 +73,10 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	struct tegra_drm *tegra = helper->dev->dev_private;
 	struct drm_device *drm = helper->dev;
 	struct drm_mode_fb_cmd2 cmd = { 0 };
+	struct fb_info *info = helper->info;
 	unsigned int bytes_per_pixel;
 	struct drm_framebuffer *fb;
 	unsigned long offset;
-	struct fb_info *info;
 	struct tegra_bo *bo;
 	size_t size;
 	int err;
@@ -97,13 +97,6 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	if (IS_ERR(bo))
 		return PTR_ERR(bo);
 
-	info = drm_fb_helper_alloc_info(helper);
-	if (IS_ERR(info)) {
-		dev_err(drm->dev, "failed to allocate framebuffer info\n");
-		drm_gem_object_put(&bo->gem);
-		return PTR_ERR(info);
-	}
-
 	fb = tegra_fb_alloc(drm,
 			    drm_get_format_info(drm, cmd.pixel_format, cmd.modifier[0]),
 			    &cmd, &bo, 1);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index c1d38d54a112..2faf8aaf98dc 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -256,8 +256,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 
 int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper);
 
-struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper);
-void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper);
 void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper);
 void drm_fb_helper_fill_info(struct fb_info *info,
 			     struct drm_fb_helper *fb_helper,
@@ -340,16 +338,6 @@ drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
 	return 0;
 }
 
-static inline struct fb_info *
-drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
-{
-	return NULL;
-}
-
-static inline void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
-{
-}
-
 static inline void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
 {
 }

base-commit: c03916cb446b6eefe91538599775bb54bf98238c
-- 
2.51.1

Re: [PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[Christian König]

On 10/27/25 09:12, Thomas Zimmermann wrote:
> Move the calls to drm_fb_helper_alloc_info() from drivers into a
> single place in fbdev helpers. Allocates struct fb_info for a new
> framebuffer device. Then call drm_fb_helper_single_fb_probe() to
> create an fbdev screen buffer. Also release the instance on errors
> by calling drm_fb_helper_release_info().
> 
> Simplifies the code and fixes the error cleanup for some of the
> drivers.
> 
> Regular release of the struct fb_info instance still happens in
> drm_fb_helper_fini() as before.
> 
> v2:
> - remove error rollback in driver implementations (kernel test robot)
> - initialize info in TTM implementation (kernel test robot)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Acked-by: Christian König <christian.koenig@amd.com> for the radeon changes.

> ---
>  drivers/gpu/drm/armada/armada_fbdev.c      | 12 +------
>  drivers/gpu/drm/drm_fb_helper.c            | 39 +++++++---------------
>  drivers/gpu/drm/drm_fbdev_dma.c            | 12 ++-----
>  drivers/gpu/drm/drm_fbdev_shmem.c          | 12 ++-----
>  drivers/gpu/drm/drm_fbdev_ttm.c            | 12 ++-----
>  drivers/gpu/drm/exynos/exynos_drm_fbdev.c  |  9 +----
>  drivers/gpu/drm/gma500/fbdev.c             | 12 +------
>  drivers/gpu/drm/i915/display/intel_fbdev.c |  9 +----
>  drivers/gpu/drm/msm/msm_fbdev.c            |  9 +----
>  drivers/gpu/drm/omapdrm/omap_fbdev.c       |  9 +----
>  drivers/gpu/drm/radeon/radeon_fbdev.c      | 13 +-------
>  drivers/gpu/drm/tegra/fbdev.c              |  9 +----
>  include/drm/drm_fb_helper.h                | 12 -------
>  13 files changed, 26 insertions(+), 143 deletions(-)
> 
> diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
> index 22e2081bfa04..601b2aad243b 100644
> --- a/drivers/gpu/drm/armada/armada_fbdev.c
> +++ b/drivers/gpu/drm/armada/armada_fbdev.c
> @@ -43,10 +43,10 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>  				    struct drm_fb_helper_surface_size *sizes)
>  {
>  	struct drm_device *dev = fbh->dev;
> +	struct fb_info *info = fbh->info;
>  	struct drm_mode_fb_cmd2 mode;
>  	struct armada_framebuffer *dfb;
>  	struct armada_gem_object *obj;
> -	struct fb_info *info;
>  	int size, ret;
>  	void *ptr;
>  
> @@ -90,12 +90,6 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>  	if (IS_ERR(dfb))
>  		return PTR_ERR(dfb);
>  
> -	info = drm_fb_helper_alloc_info(fbh);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_fballoc;
> -	}
> -
>  	info->fbops = &armada_fb_ops;
>  	info->fix.smem_start = obj->phys_addr;
>  	info->fix.smem_len = obj->obj.size;
> @@ -111,8 +105,4 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>  		(unsigned long long)obj->phys_addr);
>  
>  	return 0;
> -
> - err_fballoc:
> -	dfb->fb.funcs->destroy(&dfb->fb);
> -	return ret;
>  }
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 53e9dc0543de..dd80f5c5feec 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -495,20 +495,7 @@ int drm_fb_helper_init(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_fb_helper_init);
>  
> -/**
> - * drm_fb_helper_alloc_info - allocate fb_info and some of its members
> - * @fb_helper: driver-allocated fbdev helper
> - *
> - * A helper to alloc fb_info and the member cmap. Called by the driver
> - * within the struct &drm_driver.fbdev_probe callback function. Drivers do
> - * not need to release the allocated fb_info structure themselves, this is
> - * automatically done when calling drm_fb_helper_fini().
> - *
> - * RETURNS:
> - * fb_info pointer if things went okay, pointer containing error code
> - * otherwise
> - */
> -struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
> +static struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
>  {
>  	struct device *dev = fb_helper->dev->dev;
>  	struct fb_info *info;
> @@ -535,17 +522,8 @@ struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
>  	framebuffer_release(info);
>  	return ERR_PTR(ret);
>  }
> -EXPORT_SYMBOL(drm_fb_helper_alloc_info);
>  
> -/**
> - * drm_fb_helper_release_info - release fb_info and its members
> - * @fb_helper: driver-allocated fbdev helper
> - *
> - * A helper to release fb_info and the member cmap.  Drivers do not
> - * need to release the allocated fb_info structure themselves, this is
> - * automatically done when calling drm_fb_helper_fini().
> - */
> -void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
> +static void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
>  {
>  	struct fb_info *info = fb_helper->info;
>  
> @@ -558,7 +536,6 @@ void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
>  		fb_dealloc_cmap(&info->cmap);
>  	framebuffer_release(info);
>  }
> -EXPORT_SYMBOL(drm_fb_helper_release_info);
>  
>  /**
>   * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
> @@ -1809,6 +1786,11 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>  	height = dev->mode_config.max_height;
>  
>  	drm_client_modeset_probe(&fb_helper->client, width, height);
> +
> +	info = drm_fb_helper_alloc_info(fb_helper);
> +	if (IS_ERR(info))
> +		return PTR_ERR(info);
> +
>  	ret = drm_fb_helper_single_fb_probe(fb_helper);
>  	if (ret < 0) {
>  		if (ret == -EAGAIN) {
> @@ -1817,13 +1799,12 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>  		}
>  		mutex_unlock(&fb_helper->lock);
>  
> -		return ret;
> +		goto err_drm_fb_helper_release_info;
>  	}
>  	drm_setup_crtcs_fb(fb_helper);
>  
>  	fb_helper->deferred_setup = false;
>  
> -	info = fb_helper->info;
>  	info->var.pixclock = 0;
>  
>  	/* Need to drop locks to avoid recursive deadlock in
> @@ -1846,6 +1827,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>  	mutex_unlock(&kernel_fb_helper_lock);
>  
>  	return 0;
> +
> +err_drm_fb_helper_release_info:
> +	drm_fb_helper_release_info(fb_helper);
> +	return ret;
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c
> index c6196293e424..442d964039b7 100644
> --- a/drivers/gpu/drm/drm_fbdev_dma.c
> +++ b/drivers/gpu/drm/drm_fbdev_dma.c
> @@ -268,9 +268,9 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  {
>  	struct drm_client_dev *client = &fb_helper->client;
>  	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>  	struct drm_client_buffer *buffer;
>  	struct drm_framebuffer *fb;
> -	struct fb_info *info;
>  	u32 format;
>  	struct iosys_map map;
>  	int ret;
> @@ -300,12 +300,6 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	fb_helper->buffer = buffer;
>  	fb_helper->fb = fb;
>  
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_client_buffer_vunmap;
> -	}
> -
>  	drm_fb_helper_fill_info(info, fb_helper, sizes);
>  
>  	if (fb->funcs->dirty)
> @@ -313,12 +307,10 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	else
>  		ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
>  	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_drm_client_buffer_vunmap;
>  
>  	return 0;
>  
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>  err_drm_client_buffer_vunmap:
>  	fb_helper->fb = NULL;
>  	fb_helper->buffer = NULL;
> diff --git a/drivers/gpu/drm/drm_fbdev_shmem.c b/drivers/gpu/drm/drm_fbdev_shmem.c
> index 51573058df6f..2190e2230b83 100644
> --- a/drivers/gpu/drm/drm_fbdev_shmem.c
> +++ b/drivers/gpu/drm/drm_fbdev_shmem.c
> @@ -134,10 +134,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  {
>  	struct drm_client_dev *client = &fb_helper->client;
>  	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>  	struct drm_client_buffer *buffer;
>  	struct drm_gem_shmem_object *shmem;
>  	struct drm_framebuffer *fb;
> -	struct fb_info *info;
>  	u32 format;
>  	struct iosys_map map;
>  	int ret;
> @@ -167,12 +167,6 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	fb_helper->buffer = buffer;
>  	fb_helper->fb = fb;
>  
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_client_buffer_vunmap;
> -	}
> -
>  	drm_fb_helper_fill_info(info, fb_helper, sizes);
>  
>  	info->fbops = &drm_fbdev_shmem_fb_ops;
> @@ -193,12 +187,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	info->fbdefio = &fb_helper->fbdefio;
>  	ret = fb_deferred_io_init(info);
>  	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_drm_client_buffer_vunmap;
>  
>  	return 0;
>  
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>  err_drm_client_buffer_vunmap:
>  	fb_helper->fb = NULL;
>  	fb_helper->buffer = NULL;
> diff --git a/drivers/gpu/drm/drm_fbdev_ttm.c b/drivers/gpu/drm/drm_fbdev_ttm.c
> index ccf460fbc1f0..3a06c2b59a8d 100644
> --- a/drivers/gpu/drm/drm_fbdev_ttm.c
> +++ b/drivers/gpu/drm/drm_fbdev_ttm.c
> @@ -174,8 +174,8 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  {
>  	struct drm_client_dev *client = &fb_helper->client;
>  	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>  	struct drm_client_buffer *buffer;
> -	struct fb_info *info;
>  	size_t screen_size;
>  	void *screen_buffer;
>  	u32 format;
> @@ -203,12 +203,6 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  		goto err_drm_client_framebuffer_delete;
>  	}
>  
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_vfree;
> -	}
> -
>  	drm_fb_helper_fill_info(info, fb_helper, sizes);
>  
>  	info->fbops = &drm_fbdev_ttm_fb_ops;
> @@ -225,12 +219,10 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	info->fbdefio = &fb_helper->fbdefio;
>  	ret = fb_deferred_io_init(info);
>  	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_vfree;
>  
>  	return 0;
>  
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>  err_vfree:
>  	vfree(screen_buffer);
>  err_drm_client_framebuffer_delete:
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index a3bd21a827ad..539ce0a87886 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -57,18 +57,11 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
>  				   struct drm_fb_helper_surface_size *sizes,
>  				   struct exynos_drm_gem *exynos_gem)
>  {
> -	struct fb_info *fbi;
> +	struct fb_info *fbi = helper->info;
>  	struct drm_framebuffer *fb = helper->fb;
>  	unsigned int size = fb->width * fb->height * fb->format->cpp[0];
>  	unsigned long offset;
>  
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		DRM_DEV_ERROR(to_dma_dev(helper->dev),
> -			      "failed to allocate fb info.\n");
> -		return PTR_ERR(fbi);
> -	}
> -
>  	fbi->fbops = &exynos_drm_fb_ops;
>  
>  	drm_fb_helper_fill_info(fbi, helper, sizes);
> diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c
> index bc92fa24a1e2..c26926babc2a 100644
> --- a/drivers/gpu/drm/gma500/fbdev.c
> +++ b/drivers/gpu/drm/gma500/fbdev.c
> @@ -108,7 +108,7 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	struct drm_device *dev = fb_helper->dev;
>  	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
>  	struct pci_dev *pdev = to_pci_dev(dev->dev);
> -	struct fb_info *info;
> +	struct fb_info *info = fb_helper->info;
>  	struct drm_framebuffer *fb;
>  	struct drm_mode_fb_cmd2 mode_cmd = { };
>  	int size;
> @@ -167,12 +167,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	fb_helper->funcs = &psb_fbdev_fb_helper_funcs;
>  	fb_helper->fb = fb;
>  
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_framebuffer_unregister_private;
> -	}
> -
>  	info->fbops = &psb_fbdev_fb_ops;
>  
>  	/* Accessed stolen memory directly */
> @@ -196,10 +190,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  
>  	return 0;
>  
> -err_drm_framebuffer_unregister_private:
> -	drm_framebuffer_unregister_private(fb);
> -	drm_framebuffer_cleanup(fb);
> -	kfree(fb);
>  err_drm_gem_object_put:
>  	drm_gem_object_put(obj);
>  	return ret;
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index e5449c41cfa1..9cd03e2adeb2 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -267,8 +267,8 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  	struct intel_display *display = to_intel_display(helper->dev);
>  	struct intel_fbdev *ifbdev = to_intel_fbdev(helper);
>  	struct intel_framebuffer *fb = ifbdev->fb;
> +	struct fb_info *info = helper->info;
>  	struct ref_tracker *wakeref;
> -	struct fb_info *info;
>  	struct i915_vma *vma;
>  	unsigned long flags = 0;
>  	bool prealloc = false;
> @@ -318,13 +318,6 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  		goto out_unlock;
>  	}
>  
> -	info = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(info)) {
> -		drm_err(display->drm, "Failed to allocate fb_info (%pe)\n", info);
> -		ret = PTR_ERR(info);
> -		goto out_unpin;
> -	}
> -
>  	helper->funcs = &intel_fb_helper_funcs;
>  	helper->fb = &fb->base;
>  
> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
> index aad6fb77f0de..fd19995b12b5 100644
> --- a/drivers/gpu/drm/msm/msm_fbdev.c
> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
> @@ -91,9 +91,9 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  {
>  	struct drm_device *dev = helper->dev;
>  	struct msm_drm_private *priv = dev->dev_private;
> +	struct fb_info *fbi = helper->info;
>  	struct drm_framebuffer *fb = NULL;
>  	struct drm_gem_object *bo;
> -	struct fb_info *fbi = NULL;
>  	uint64_t paddr;
>  	uint32_t format;
>  	int ret, pitch;
> @@ -126,13 +126,6 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  		goto fail;
>  	}
>  
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		DRM_DEV_ERROR(dev->dev, "failed to allocate fb info\n");
> -		ret = PTR_ERR(fbi);
> -		goto fail;
> -	}
> -
>  	DBG("fbi=%p, dev=%p", fbi, dev);
>  
>  	helper->funcs = &msm_fbdev_helper_funcs;
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index b5df2923d2a6..c4671ab87f9c 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -153,9 +153,9 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  	struct drm_device *dev = helper->dev;
>  	struct omap_drm_private *priv = dev->dev_private;
>  	struct omap_fbdev *fbdev = priv->fbdev;
> +	struct fb_info *fbi = helper->info;
>  	struct drm_framebuffer *fb = NULL;
>  	union omap_gem_size gsize;
> -	struct fb_info *fbi = NULL;
>  	struct drm_mode_fb_cmd2 mode_cmd = {0};
>  	struct drm_gem_object *bo;
>  	dma_addr_t dma_addr;
> @@ -224,13 +224,6 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  		goto fail;
>  	}
>  
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		dev_err(dev->dev, "failed to allocate fb info\n");
> -		ret = PTR_ERR(fbi);
> -		goto fail;
> -	}
> -
>  	DBG("fbi=%p, dev=%p", fbi, dev);
>  
>  	helper->funcs = &omap_fbdev_helper_funcs;
> diff --git a/drivers/gpu/drm/radeon/radeon_fbdev.c b/drivers/gpu/drm/radeon/radeon_fbdev.c
> index 4df6c9167bf0..1b469b2b4b04 100644
> --- a/drivers/gpu/drm/radeon/radeon_fbdev.c
> +++ b/drivers/gpu/drm/radeon/radeon_fbdev.c
> @@ -204,7 +204,7 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	struct radeon_device *rdev = fb_helper->dev->dev_private;
>  	const struct drm_format_info *format_info;
>  	struct drm_mode_fb_cmd2 mode_cmd = { };
> -	struct fb_info *info;
> +	struct fb_info *info = fb_helper->info;
>  	struct drm_gem_object *gobj;
>  	struct radeon_bo *rbo;
>  	struct drm_framebuffer *fb;
> @@ -245,13 +245,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  	fb_helper->funcs = &radeon_fbdev_fb_helper_funcs;
>  	fb_helper->fb = fb;
>  
> -	/* okay we have an object now allocate the framebuffer */
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_framebuffer_unregister_private;
> -	}
> -
>  	info->fbops = &radeon_fbdev_fb_ops;
>  
>  	/* radeon resume is fragile and needs a vt switch to help it along */
> @@ -277,10 +270,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>  
>  	return 0;
>  
> -err_drm_framebuffer_unregister_private:
> -	fb_helper->fb = NULL;
> -	drm_framebuffer_unregister_private(fb);
> -	drm_framebuffer_cleanup(fb);
>  err_kfree:
>  	kfree(fb);
>  err_radeon_fbdev_destroy_pinned_object:
> diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
> index 91aece6f34e0..8f40882aa76e 100644
> --- a/drivers/gpu/drm/tegra/fbdev.c
> +++ b/drivers/gpu/drm/tegra/fbdev.c
> @@ -73,10 +73,10 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  	struct tegra_drm *tegra = helper->dev->dev_private;
>  	struct drm_device *drm = helper->dev;
>  	struct drm_mode_fb_cmd2 cmd = { 0 };
> +	struct fb_info *info = helper->info;
>  	unsigned int bytes_per_pixel;
>  	struct drm_framebuffer *fb;
>  	unsigned long offset;
> -	struct fb_info *info;
>  	struct tegra_bo *bo;
>  	size_t size;
>  	int err;
> @@ -97,13 +97,6 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  	if (IS_ERR(bo))
>  		return PTR_ERR(bo);
>  
> -	info = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(info)) {
> -		dev_err(drm->dev, "failed to allocate framebuffer info\n");
> -		drm_gem_object_put(&bo->gem);
> -		return PTR_ERR(info);
> -	}
> -
>  	fb = tegra_fb_alloc(drm,
>  			    drm_get_format_info(drm, cmd.pixel_format, cmd.modifier[0]),
>  			    &cmd, &bo, 1);
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index c1d38d54a112..2faf8aaf98dc 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -256,8 +256,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
>  
>  int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper);
>  
> -struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper);
> -void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper);
>  void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper);
>  void drm_fb_helper_fill_info(struct fb_info *info,
>  			     struct drm_fb_helper *fb_helper,
> @@ -340,16 +338,6 @@ drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
>  	return 0;
>  }
>  
> -static inline struct fb_info *
> -drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
> -{
> -	return NULL;
> -}
> -
> -static inline void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
> -{
> -}
> -
>  static inline void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
>  {
>  }
> 
> base-commit: c03916cb446b6eefe91538599775bb54bf98238c

Re: [PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[Dmitry Baryshkov]

On Tue, Oct 28, 2025 at 08:58:10AM +0100, Christian König wrote:
> On 10/27/25 09:12, Thomas Zimmermann wrote:
> > Move the calls to drm_fb_helper_alloc_info() from drivers into a
> > single place in fbdev helpers. Allocates struct fb_info for a new
> > framebuffer device. Then call drm_fb_helper_single_fb_probe() to
> > create an fbdev screen buffer. Also release the instance on errors
> > by calling drm_fb_helper_release_info().
> > 
> > Simplifies the code and fixes the error cleanup for some of the
> > drivers.
> > 
> > Regular release of the struct fb_info instance still happens in
> > drm_fb_helper_fini() as before.
> > 
> > v2:
> > - remove error rollback in driver implementations (kernel test robot)
> > - initialize info in TTM implementation (kernel test robot)
> > 
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> 
> Acked-by: Christian König <christian.koenig@amd.com> for the radeon changes.
> 

Acked-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> # msm


-- 
With best wishes
Dmitry

Re: [PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[Thomas Zimmermann]

ping for more reviews

Am 27.10.25 um 09:12 schrieb Thomas Zimmermann:
> Move the calls to drm_fb_helper_alloc_info() from drivers into a
> single place in fbdev helpers. Allocates struct fb_info for a new
> framebuffer device. Then call drm_fb_helper_single_fb_probe() to
> create an fbdev screen buffer. Also release the instance on errors
> by calling drm_fb_helper_release_info().
>
> Simplifies the code and fixes the error cleanup for some of the
> drivers.
>
> Regular release of the struct fb_info instance still happens in
> drm_fb_helper_fini() as before.
>
> v2:
> - remove error rollback in driver implementations (kernel test robot)
> - initialize info in TTM implementation (kernel test robot)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   drivers/gpu/drm/armada/armada_fbdev.c      | 12 +------
>   drivers/gpu/drm/drm_fb_helper.c            | 39 +++++++---------------
>   drivers/gpu/drm/drm_fbdev_dma.c            | 12 ++-----
>   drivers/gpu/drm/drm_fbdev_shmem.c          | 12 ++-----
>   drivers/gpu/drm/drm_fbdev_ttm.c            | 12 ++-----
>   drivers/gpu/drm/exynos/exynos_drm_fbdev.c  |  9 +----
>   drivers/gpu/drm/gma500/fbdev.c             | 12 +------
>   drivers/gpu/drm/i915/display/intel_fbdev.c |  9 +----
>   drivers/gpu/drm/msm/msm_fbdev.c            |  9 +----
>   drivers/gpu/drm/omapdrm/omap_fbdev.c       |  9 +----
>   drivers/gpu/drm/radeon/radeon_fbdev.c      | 13 +-------
>   drivers/gpu/drm/tegra/fbdev.c              |  9 +----
>   include/drm/drm_fb_helper.h                | 12 -------
>   13 files changed, 26 insertions(+), 143 deletions(-)
>
> diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
> index 22e2081bfa04..601b2aad243b 100644
> --- a/drivers/gpu/drm/armada/armada_fbdev.c
> +++ b/drivers/gpu/drm/armada/armada_fbdev.c
> @@ -43,10 +43,10 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>   				    struct drm_fb_helper_surface_size *sizes)
>   {
>   	struct drm_device *dev = fbh->dev;
> +	struct fb_info *info = fbh->info;
>   	struct drm_mode_fb_cmd2 mode;
>   	struct armada_framebuffer *dfb;
>   	struct armada_gem_object *obj;
> -	struct fb_info *info;
>   	int size, ret;
>   	void *ptr;
>   
> @@ -90,12 +90,6 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>   	if (IS_ERR(dfb))
>   		return PTR_ERR(dfb);
>   
> -	info = drm_fb_helper_alloc_info(fbh);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_fballoc;
> -	}
> -
>   	info->fbops = &armada_fb_ops;
>   	info->fix.smem_start = obj->phys_addr;
>   	info->fix.smem_len = obj->obj.size;
> @@ -111,8 +105,4 @@ int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
>   		(unsigned long long)obj->phys_addr);
>   
>   	return 0;
> -
> - err_fballoc:
> -	dfb->fb.funcs->destroy(&dfb->fb);
> -	return ret;
>   }
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 53e9dc0543de..dd80f5c5feec 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -495,20 +495,7 @@ int drm_fb_helper_init(struct drm_device *dev,
>   }
>   EXPORT_SYMBOL(drm_fb_helper_init);
>   
> -/**
> - * drm_fb_helper_alloc_info - allocate fb_info and some of its members
> - * @fb_helper: driver-allocated fbdev helper
> - *
> - * A helper to alloc fb_info and the member cmap. Called by the driver
> - * within the struct &drm_driver.fbdev_probe callback function. Drivers do
> - * not need to release the allocated fb_info structure themselves, this is
> - * automatically done when calling drm_fb_helper_fini().
> - *
> - * RETURNS:
> - * fb_info pointer if things went okay, pointer containing error code
> - * otherwise
> - */
> -struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
> +static struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
>   {
>   	struct device *dev = fb_helper->dev->dev;
>   	struct fb_info *info;
> @@ -535,17 +522,8 @@ struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
>   	framebuffer_release(info);
>   	return ERR_PTR(ret);
>   }
> -EXPORT_SYMBOL(drm_fb_helper_alloc_info);
>   
> -/**
> - * drm_fb_helper_release_info - release fb_info and its members
> - * @fb_helper: driver-allocated fbdev helper
> - *
> - * A helper to release fb_info and the member cmap.  Drivers do not
> - * need to release the allocated fb_info structure themselves, this is
> - * automatically done when calling drm_fb_helper_fini().
> - */
> -void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
> +static void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
>   {
>   	struct fb_info *info = fb_helper->info;
>   
> @@ -558,7 +536,6 @@ void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
>   		fb_dealloc_cmap(&info->cmap);
>   	framebuffer_release(info);
>   }
> -EXPORT_SYMBOL(drm_fb_helper_release_info);
>   
>   /**
>    * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
> @@ -1809,6 +1786,11 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>   	height = dev->mode_config.max_height;
>   
>   	drm_client_modeset_probe(&fb_helper->client, width, height);
> +
> +	info = drm_fb_helper_alloc_info(fb_helper);
> +	if (IS_ERR(info))
> +		return PTR_ERR(info);
> +
>   	ret = drm_fb_helper_single_fb_probe(fb_helper);
>   	if (ret < 0) {
>   		if (ret == -EAGAIN) {
> @@ -1817,13 +1799,12 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>   		}
>   		mutex_unlock(&fb_helper->lock);
>   
> -		return ret;
> +		goto err_drm_fb_helper_release_info;
>   	}
>   	drm_setup_crtcs_fb(fb_helper);
>   
>   	fb_helper->deferred_setup = false;
>   
> -	info = fb_helper->info;
>   	info->var.pixclock = 0;
>   
>   	/* Need to drop locks to avoid recursive deadlock in
> @@ -1846,6 +1827,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
>   	mutex_unlock(&kernel_fb_helper_lock);
>   
>   	return 0;
> +
> +err_drm_fb_helper_release_info:
> +	drm_fb_helper_release_info(fb_helper);
> +	return ret;
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c
> index c6196293e424..442d964039b7 100644
> --- a/drivers/gpu/drm/drm_fbdev_dma.c
> +++ b/drivers/gpu/drm/drm_fbdev_dma.c
> @@ -268,9 +268,9 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   {
>   	struct drm_client_dev *client = &fb_helper->client;
>   	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>   	struct drm_client_buffer *buffer;
>   	struct drm_framebuffer *fb;
> -	struct fb_info *info;
>   	u32 format;
>   	struct iosys_map map;
>   	int ret;
> @@ -300,12 +300,6 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	fb_helper->buffer = buffer;
>   	fb_helper->fb = fb;
>   
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_client_buffer_vunmap;
> -	}
> -
>   	drm_fb_helper_fill_info(info, fb_helper, sizes);
>   
>   	if (fb->funcs->dirty)
> @@ -313,12 +307,10 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	else
>   		ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
>   	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_drm_client_buffer_vunmap;
>   
>   	return 0;
>   
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>   err_drm_client_buffer_vunmap:
>   	fb_helper->fb = NULL;
>   	fb_helper->buffer = NULL;
> diff --git a/drivers/gpu/drm/drm_fbdev_shmem.c b/drivers/gpu/drm/drm_fbdev_shmem.c
> index 51573058df6f..2190e2230b83 100644
> --- a/drivers/gpu/drm/drm_fbdev_shmem.c
> +++ b/drivers/gpu/drm/drm_fbdev_shmem.c
> @@ -134,10 +134,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   {
>   	struct drm_client_dev *client = &fb_helper->client;
>   	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>   	struct drm_client_buffer *buffer;
>   	struct drm_gem_shmem_object *shmem;
>   	struct drm_framebuffer *fb;
> -	struct fb_info *info;
>   	u32 format;
>   	struct iosys_map map;
>   	int ret;
> @@ -167,12 +167,6 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	fb_helper->buffer = buffer;
>   	fb_helper->fb = fb;
>   
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_client_buffer_vunmap;
> -	}
> -
>   	drm_fb_helper_fill_info(info, fb_helper, sizes);
>   
>   	info->fbops = &drm_fbdev_shmem_fb_ops;
> @@ -193,12 +187,10 @@ int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	info->fbdefio = &fb_helper->fbdefio;
>   	ret = fb_deferred_io_init(info);
>   	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_drm_client_buffer_vunmap;
>   
>   	return 0;
>   
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>   err_drm_client_buffer_vunmap:
>   	fb_helper->fb = NULL;
>   	fb_helper->buffer = NULL;
> diff --git a/drivers/gpu/drm/drm_fbdev_ttm.c b/drivers/gpu/drm/drm_fbdev_ttm.c
> index ccf460fbc1f0..3a06c2b59a8d 100644
> --- a/drivers/gpu/drm/drm_fbdev_ttm.c
> +++ b/drivers/gpu/drm/drm_fbdev_ttm.c
> @@ -174,8 +174,8 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   {
>   	struct drm_client_dev *client = &fb_helper->client;
>   	struct drm_device *dev = fb_helper->dev;
> +	struct fb_info *info = fb_helper->info;
>   	struct drm_client_buffer *buffer;
> -	struct fb_info *info;
>   	size_t screen_size;
>   	void *screen_buffer;
>   	u32 format;
> @@ -203,12 +203,6 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   		goto err_drm_client_framebuffer_delete;
>   	}
>   
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_vfree;
> -	}
> -
>   	drm_fb_helper_fill_info(info, fb_helper, sizes);
>   
>   	info->fbops = &drm_fbdev_ttm_fb_ops;
> @@ -225,12 +219,10 @@ int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	info->fbdefio = &fb_helper->fbdefio;
>   	ret = fb_deferred_io_init(info);
>   	if (ret)
> -		goto err_drm_fb_helper_release_info;
> +		goto err_vfree;
>   
>   	return 0;
>   
> -err_drm_fb_helper_release_info:
> -	drm_fb_helper_release_info(fb_helper);
>   err_vfree:
>   	vfree(screen_buffer);
>   err_drm_client_framebuffer_delete:
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index a3bd21a827ad..539ce0a87886 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -57,18 +57,11 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
>   				   struct drm_fb_helper_surface_size *sizes,
>   				   struct exynos_drm_gem *exynos_gem)
>   {
> -	struct fb_info *fbi;
> +	struct fb_info *fbi = helper->info;
>   	struct drm_framebuffer *fb = helper->fb;
>   	unsigned int size = fb->width * fb->height * fb->format->cpp[0];
>   	unsigned long offset;
>   
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		DRM_DEV_ERROR(to_dma_dev(helper->dev),
> -			      "failed to allocate fb info.\n");
> -		return PTR_ERR(fbi);
> -	}
> -
>   	fbi->fbops = &exynos_drm_fb_ops;
>   
>   	drm_fb_helper_fill_info(fbi, helper, sizes);
> diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c
> index bc92fa24a1e2..c26926babc2a 100644
> --- a/drivers/gpu/drm/gma500/fbdev.c
> +++ b/drivers/gpu/drm/gma500/fbdev.c
> @@ -108,7 +108,7 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	struct drm_device *dev = fb_helper->dev;
>   	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
>   	struct pci_dev *pdev = to_pci_dev(dev->dev);
> -	struct fb_info *info;
> +	struct fb_info *info = fb_helper->info;
>   	struct drm_framebuffer *fb;
>   	struct drm_mode_fb_cmd2 mode_cmd = { };
>   	int size;
> @@ -167,12 +167,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	fb_helper->funcs = &psb_fbdev_fb_helper_funcs;
>   	fb_helper->fb = fb;
>   
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_framebuffer_unregister_private;
> -	}
> -
>   	info->fbops = &psb_fbdev_fb_ops;
>   
>   	/* Accessed stolen memory directly */
> @@ -196,10 +190,6 @@ int psb_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   
>   	return 0;
>   
> -err_drm_framebuffer_unregister_private:
> -	drm_framebuffer_unregister_private(fb);
> -	drm_framebuffer_cleanup(fb);
> -	kfree(fb);
>   err_drm_gem_object_put:
>   	drm_gem_object_put(obj);
>   	return ret;
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index e5449c41cfa1..9cd03e2adeb2 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -267,8 +267,8 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   	struct intel_display *display = to_intel_display(helper->dev);
>   	struct intel_fbdev *ifbdev = to_intel_fbdev(helper);
>   	struct intel_framebuffer *fb = ifbdev->fb;
> +	struct fb_info *info = helper->info;
>   	struct ref_tracker *wakeref;
> -	struct fb_info *info;
>   	struct i915_vma *vma;
>   	unsigned long flags = 0;
>   	bool prealloc = false;
> @@ -318,13 +318,6 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   		goto out_unlock;
>   	}
>   
> -	info = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(info)) {
> -		drm_err(display->drm, "Failed to allocate fb_info (%pe)\n", info);
> -		ret = PTR_ERR(info);
> -		goto out_unpin;
> -	}
> -
>   	helper->funcs = &intel_fb_helper_funcs;
>   	helper->fb = &fb->base;
>   
> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
> index aad6fb77f0de..fd19995b12b5 100644
> --- a/drivers/gpu/drm/msm/msm_fbdev.c
> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
> @@ -91,9 +91,9 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   {
>   	struct drm_device *dev = helper->dev;
>   	struct msm_drm_private *priv = dev->dev_private;
> +	struct fb_info *fbi = helper->info;
>   	struct drm_framebuffer *fb = NULL;
>   	struct drm_gem_object *bo;
> -	struct fb_info *fbi = NULL;
>   	uint64_t paddr;
>   	uint32_t format;
>   	int ret, pitch;
> @@ -126,13 +126,6 @@ int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   		goto fail;
>   	}
>   
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		DRM_DEV_ERROR(dev->dev, "failed to allocate fb info\n");
> -		ret = PTR_ERR(fbi);
> -		goto fail;
> -	}
> -
>   	DBG("fbi=%p, dev=%p", fbi, dev);
>   
>   	helper->funcs = &msm_fbdev_helper_funcs;
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index b5df2923d2a6..c4671ab87f9c 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -153,9 +153,9 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   	struct drm_device *dev = helper->dev;
>   	struct omap_drm_private *priv = dev->dev_private;
>   	struct omap_fbdev *fbdev = priv->fbdev;
> +	struct fb_info *fbi = helper->info;
>   	struct drm_framebuffer *fb = NULL;
>   	union omap_gem_size gsize;
> -	struct fb_info *fbi = NULL;
>   	struct drm_mode_fb_cmd2 mode_cmd = {0};
>   	struct drm_gem_object *bo;
>   	dma_addr_t dma_addr;
> @@ -224,13 +224,6 @@ int omap_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   		goto fail;
>   	}
>   
> -	fbi = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(fbi)) {
> -		dev_err(dev->dev, "failed to allocate fb info\n");
> -		ret = PTR_ERR(fbi);
> -		goto fail;
> -	}
> -
>   	DBG("fbi=%p, dev=%p", fbi, dev);
>   
>   	helper->funcs = &omap_fbdev_helper_funcs;
> diff --git a/drivers/gpu/drm/radeon/radeon_fbdev.c b/drivers/gpu/drm/radeon/radeon_fbdev.c
> index 4df6c9167bf0..1b469b2b4b04 100644
> --- a/drivers/gpu/drm/radeon/radeon_fbdev.c
> +++ b/drivers/gpu/drm/radeon/radeon_fbdev.c
> @@ -204,7 +204,7 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	struct radeon_device *rdev = fb_helper->dev->dev_private;
>   	const struct drm_format_info *format_info;
>   	struct drm_mode_fb_cmd2 mode_cmd = { };
> -	struct fb_info *info;
> +	struct fb_info *info = fb_helper->info;
>   	struct drm_gem_object *gobj;
>   	struct radeon_bo *rbo;
>   	struct drm_framebuffer *fb;
> @@ -245,13 +245,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   	fb_helper->funcs = &radeon_fbdev_fb_helper_funcs;
>   	fb_helper->fb = fb;
>   
> -	/* okay we have an object now allocate the framebuffer */
> -	info = drm_fb_helper_alloc_info(fb_helper);
> -	if (IS_ERR(info)) {
> -		ret = PTR_ERR(info);
> -		goto err_drm_framebuffer_unregister_private;
> -	}
> -
>   	info->fbops = &radeon_fbdev_fb_ops;
>   
>   	/* radeon resume is fragile and needs a vt switch to help it along */
> @@ -277,10 +270,6 @@ int radeon_fbdev_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
>   
>   	return 0;
>   
> -err_drm_framebuffer_unregister_private:
> -	fb_helper->fb = NULL;
> -	drm_framebuffer_unregister_private(fb);
> -	drm_framebuffer_cleanup(fb);
>   err_kfree:
>   	kfree(fb);
>   err_radeon_fbdev_destroy_pinned_object:
> diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
> index 91aece6f34e0..8f40882aa76e 100644
> --- a/drivers/gpu/drm/tegra/fbdev.c
> +++ b/drivers/gpu/drm/tegra/fbdev.c
> @@ -73,10 +73,10 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   	struct tegra_drm *tegra = helper->dev->dev_private;
>   	struct drm_device *drm = helper->dev;
>   	struct drm_mode_fb_cmd2 cmd = { 0 };
> +	struct fb_info *info = helper->info;
>   	unsigned int bytes_per_pixel;
>   	struct drm_framebuffer *fb;
>   	unsigned long offset;
> -	struct fb_info *info;
>   	struct tegra_bo *bo;
>   	size_t size;
>   	int err;
> @@ -97,13 +97,6 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>   	if (IS_ERR(bo))
>   		return PTR_ERR(bo);
>   
> -	info = drm_fb_helper_alloc_info(helper);
> -	if (IS_ERR(info)) {
> -		dev_err(drm->dev, "failed to allocate framebuffer info\n");
> -		drm_gem_object_put(&bo->gem);
> -		return PTR_ERR(info);
> -	}
> -
>   	fb = tegra_fb_alloc(drm,
>   			    drm_get_format_info(drm, cmd.pixel_format, cmd.modifier[0]),
>   			    &cmd, &bo, 1);
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index c1d38d54a112..2faf8aaf98dc 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -256,8 +256,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
>   
>   int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper);
>   
> -struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper);
> -void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper);
>   void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper);
>   void drm_fb_helper_fill_info(struct fb_info *info,
>   			     struct drm_fb_helper *fb_helper,
> @@ -340,16 +338,6 @@ drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
>   	return 0;
>   }
>   
> -static inline struct fb_info *
> -drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
> -{
> -	return NULL;
> -}
> -
> -static inline void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
> -{
> -}
> -
>   static inline void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
>   {
>   }
>
> base-commit: c03916cb446b6eefe91538599775bb54bf98238c

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

Re: [PATCH v2] drm/fb-helper: Allocate and release fb_info in single place

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann@suse.de> writes:

Hello Thomas,

> Move the calls to drm_fb_helper_alloc_info() from drivers into a
> single place in fbdev helpers. Allocates struct fb_info for a new
> framebuffer device. Then call drm_fb_helper_single_fb_probe() to
> create an fbdev screen buffer. Also release the instance on errors
> by calling drm_fb_helper_release_info().
>
> Simplifies the code and fixes the error cleanup for some of the
> drivers.
>
> Regular release of the struct fb_info instance still happens in
> drm_fb_helper_fini() as before.
>
> v2:
> - remove error rollback in driver implementations (kernel test robot)
> - initialize info in TTM implementation (kernel test robot)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

It simplifies the drivers' code indeed.

Acked-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat