From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Tue, 21 Apr 2026 07:29:08 +0000 (+0200)
Subject: drm/tegra: fbdev: Use a DRM client buffer
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=0daa4b50fc6a6e636f4f0b2b462860f36ef67a6a;p=thirdparty%2Flinux.git

drm/tegra: fbdev: Use a DRM client buffer

Replace the internal DRM framebuffer with a DRM client buffer. The
client buffer allocates the DRM framebuffer on a file and also uses
GEM object handles via the regular ADDFB2 interfaces.

Using client-buffer interfaces unifies framebuffer allocation for
DRM clients in user space and tegra's internal fbdev emulation. It
also simplifies the clean-up side of the fbdev emulation.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20260421073646.144712-5-tzimmermann@suse.de
---

diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
index bcf32cfcf8180..003e80cf7b9a1 100644
--- a/drivers/gpu/drm/tegra/fbdev.c
+++ b/drivers/gpu/drm/tegra/fbdev.c
@@ -40,8 +40,7 @@ static int tegra_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 static void tegra_fbdev_fb_destroy(struct fb_info *info)
 {
 	struct drm_fb_helper *helper = info->par;
-	struct drm_framebuffer *fb = helper->fb;
-	struct tegra_bo *bo = tegra_fb_get_plane(fb, 0);
+	struct tegra_bo *bo = tegra_fb_get_plane(helper->fb, 0);
 
 	drm_fb_helper_fini(helper);
 
@@ -50,8 +49,8 @@ static void tegra_fbdev_fb_destroy(struct fb_info *info)
 		vunmap(bo->vaddr);
 		bo->vaddr = NULL;
 	}
-	drm_framebuffer_remove(fb);
 
+	drm_client_buffer_delete(helper->buffer);
 	drm_client_release(&helper->client);
 }
 
@@ -70,15 +69,18 @@ static const struct drm_fb_helper_funcs tegra_fbdev_helper_funcs = {
 int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 				   struct drm_fb_helper_surface_size *sizes)
 {
-	struct tegra_drm *tegra = helper->dev->dev_private;
-	struct drm_device *drm = helper->dev;
-	struct drm_mode_fb_cmd2 cmd = { 0 };
+	struct drm_client_dev *client = &helper->client;
+	struct drm_device *drm = client->dev;
+	struct drm_file *file = client->file;
+	struct tegra_drm *tegra = drm->dev_private;
 	struct fb_info *info = helper->info;
 	u32 fourcc, pitch;
 	u64 size;
 	const struct drm_format_info *format;
-	struct drm_framebuffer *fb;
 	struct tegra_bo *bo;
+	struct drm_gem_object *gem;
+	u32 handle;
+	struct drm_client_buffer *buffer;
 	int err;
 
 	fourcc = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
@@ -90,23 +92,22 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	bo = tegra_bo_create(drm, size, 0);
 	if (IS_ERR(bo))
 		return PTR_ERR(bo);
+	gem = &bo->gem;
 
-	cmd.pixel_format = fourcc;
-	cmd.width = sizes->surface_width;
-	cmd.height = sizes->surface_height;
-	cmd.pitches[0] = pitch;
-
-	fb = tegra_fb_alloc(drm, format, &cmd, &bo, 1);
-	if (IS_ERR(fb)) {
-		err = PTR_ERR(fb);
-		dev_err(drm->dev, "failed to allocate DRM framebuffer: %d\n",
-			err);
-		drm_gem_object_put(&bo->gem);
-		return PTR_ERR(fb);
+	err = drm_gem_handle_create(file, gem, &handle);
+	if (err)
+		goto err_drm_gem_object_put;
+
+	buffer = drm_client_buffer_create(client, sizes->surface_width, sizes->surface_height,
+					  fourcc, handle, pitch);
+	if (IS_ERR(buffer)) {
+		err = PTR_ERR(buffer);
+		goto err_drm_gem_handle_delete;
 	}
 
 	helper->funcs = &tegra_fbdev_helper_funcs;
-	helper->fb = fb;
+	helper->buffer = buffer;
+	helper->fb = buffer->fb;
 
 	info->fbops = &tegra_fb_ops;
 
@@ -118,19 +119,29 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 		if (!bo->vaddr) {
 			dev_err(drm->dev, "failed to vmap() framebuffer\n");
 			err = -ENOMEM;
-			goto destroy;
+			goto err_drm_client_buffer_delete;
 		}
 	}
 
 	info->flags |= FBINFO_VIRTFB;
 	info->screen_buffer = bo->vaddr;
-	info->screen_size = bo->gem.size;
+	info->screen_size = gem->size;
 	info->fix.smem_start = (unsigned long)(bo->iova);
-	info->fix.smem_len = bo->gem.size;
+	info->fix.smem_len = gem->size;
+
+	/* The handle is only needed for creating the framebuffer. */
+	drm_gem_handle_delete(file, handle);
+
+	/* The framebuffer still holds a reference on the GEM object. */
+	drm_gem_object_put(gem);
 
 	return 0;
 
-destroy:
-	drm_framebuffer_remove(fb);
+err_drm_client_buffer_delete:
+	drm_client_buffer_delete(buffer);
+err_drm_gem_handle_delete:
+	drm_gem_handle_delete(file, handle);
+err_drm_gem_object_put:
+	drm_gem_object_put(gem);
 	return err;
 }