Re: [PATCH 1/4] drm/client: Add client free callback to unprepare fb_helper

[Thomas Zimmermann <tzimmermann@suse.de>]

Am 09.10.25 um 15:16 schrieb Thomas Zimmermann:
> Add free callback to struct drm_client_funcs. Invoke function to
> free the client memory as part of the release process. Implement
> free for fbdev emulation.
>
> Fbdev emulation allocates and prepares client memory in
> drm_fbdev_client_setup(). The release happens in fb_destroy from
> struct fb_ops. Multiple implementations of this callback exist in
> the various drivers that provide fbdev implementation. Each of them
> needs to follow the implementation details of the fbdev setup code.
>
> Adding a free callback for the client puts the unprepare and release
> of the fbdev client in a single place.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Acked-by: Alex Deucher <alexander.deucher@amd.com>

via irc

https://people.freedesktop.org/~cbrill/dri-log/?channel=radeon&highlight_names=&date=2025-10-23&show_html=true

> ---
>   drivers/gpu/drm/armada/armada_fbdev.c      |  2 --
>   drivers/gpu/drm/clients/drm_fbdev_client.c | 17 +++++++++++++++--
>   drivers/gpu/drm/drm_client.c               |  4 ++++
>   drivers/gpu/drm/drm_fbdev_dma.c            |  4 ----
>   drivers/gpu/drm/drm_fbdev_shmem.c          |  2 --
>   drivers/gpu/drm/drm_fbdev_ttm.c            |  2 --
>   drivers/gpu/drm/exynos/exynos_drm_fbdev.c  |  2 --
>   drivers/gpu/drm/gma500/fbdev.c             |  3 ---
>   drivers/gpu/drm/i915/display/intel_fbdev.c |  2 --
>   drivers/gpu/drm/msm/msm_fbdev.c            |  2 --
>   drivers/gpu/drm/omapdrm/omap_fbdev.c       |  2 --
>   drivers/gpu/drm/radeon/radeon_fbdev.c      |  2 --
>   drivers/gpu/drm/tegra/fbdev.c              |  2 --
>   include/drm/drm_client.h                   | 10 ++++++++++
>   14 files changed, 29 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
> index cb53cc91bafb..22e2081bfa04 100644
> --- a/drivers/gpu/drm/armada/armada_fbdev.c
> +++ b/drivers/gpu/drm/armada/armada_fbdev.c
> @@ -28,8 +28,6 @@ static void armada_fbdev_fb_destroy(struct fb_info *info)
>   	fbh->fb->funcs->destroy(fbh->fb);
>   
>   	drm_client_release(&fbh->client);
> -	drm_fb_helper_unprepare(fbh);
> -	kfree(fbh);
>   }
>   
>   static const struct fb_ops armada_fb_ops = {
> diff --git a/drivers/gpu/drm/clients/drm_fbdev_client.c b/drivers/gpu/drm/clients/drm_fbdev_client.c
> index f894ba52bdb5..5336accab1b6 100644
> --- a/drivers/gpu/drm/clients/drm_fbdev_client.c
> +++ b/drivers/gpu/drm/clients/drm_fbdev_client.c
> @@ -13,16 +13,28 @@
>    * struct drm_client_funcs
>    */
>   
> +static void drm_fbdev_client_free(struct drm_client_dev *client)
> +{
> +	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
> +
> +	drm_fb_helper_unprepare(fb_helper);
> +	kfree(fb_helper);
> +}
> +
>   static void drm_fbdev_client_unregister(struct drm_client_dev *client)
>   {
>   	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
>   
>   	if (fb_helper->info) {
> +		/*
> +		 * Fully probed framebuffer device
> +		 */
>   		drm_fb_helper_unregister_info(fb_helper);
>   	} else {
> +		/*
> +		 * Partially initialized client, no framebuffer device yet
> +		 */
>   		drm_client_release(&fb_helper->client);
> -		drm_fb_helper_unprepare(fb_helper);
> -		kfree(fb_helper);
>   	}
>   }
>   
> @@ -88,6 +100,7 @@ static int drm_fbdev_client_resume(struct drm_client_dev *client, bool holds_con
>   
>   static const struct drm_client_funcs drm_fbdev_client_funcs = {
>   	.owner		= THIS_MODULE,
> +	.free		= drm_fbdev_client_free,
>   	.unregister	= drm_fbdev_client_unregister,
>   	.restore	= drm_fbdev_client_restore,
>   	.hotplug	= drm_fbdev_client_hotplug,
> diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
> index 3fa38d4ac70b..fe9c6d7083ea 100644
> --- a/drivers/gpu/drm/drm_client.c
> +++ b/drivers/gpu/drm/drm_client.c
> @@ -168,6 +168,10 @@ void drm_client_release(struct drm_client_dev *client)
>   
>   	drm_client_modeset_free(client);
>   	drm_client_close(client);
> +
> +	if (client->funcs && client->funcs->free)
> +		client->funcs->free(client);
> +
>   	drm_dev_put(dev);
>   }
>   EXPORT_SYMBOL(drm_client_release);
> diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c
> index 8bd626ef16c7..c6196293e424 100644
> --- a/drivers/gpu/drm/drm_fbdev_dma.c
> +++ b/drivers/gpu/drm/drm_fbdev_dma.c
> @@ -57,8 +57,6 @@ static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
>   	drm_client_buffer_vunmap(fb_helper->buffer);
>   	drm_client_framebuffer_delete(fb_helper->buffer);
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops drm_fbdev_dma_fb_ops = {
> @@ -92,8 +90,6 @@ static void drm_fbdev_dma_shadowed_fb_destroy(struct fb_info *info)
>   	drm_client_buffer_vunmap(fb_helper->buffer);
>   	drm_client_framebuffer_delete(fb_helper->buffer);
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops drm_fbdev_dma_shadowed_fb_ops = {
> diff --git a/drivers/gpu/drm/drm_fbdev_shmem.c b/drivers/gpu/drm/drm_fbdev_shmem.c
> index 1e827bf8b815..51573058df6f 100644
> --- a/drivers/gpu/drm/drm_fbdev_shmem.c
> +++ b/drivers/gpu/drm/drm_fbdev_shmem.c
> @@ -65,8 +65,6 @@ static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
>   	drm_client_buffer_vunmap(fb_helper->buffer);
>   	drm_client_framebuffer_delete(fb_helper->buffer);
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops drm_fbdev_shmem_fb_ops = {
> diff --git a/drivers/gpu/drm/drm_fbdev_ttm.c b/drivers/gpu/drm/drm_fbdev_ttm.c
> index 85feb55bba11..ccf460fbc1f0 100644
> --- a/drivers/gpu/drm/drm_fbdev_ttm.c
> +++ b/drivers/gpu/drm/drm_fbdev_ttm.c
> @@ -53,8 +53,6 @@ static void drm_fbdev_ttm_fb_destroy(struct fb_info *info)
>   	drm_client_framebuffer_delete(fb_helper->buffer);
>   
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops drm_fbdev_ttm_fb_ops = {
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index 93de25b77e68..a3bd21a827ad 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -42,8 +42,6 @@ static void exynos_drm_fb_destroy(struct fb_info *info)
>   	drm_framebuffer_remove(fb);
>   
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops exynos_drm_fb_ops = {
> diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c
> index a6af21514cff..bc92fa24a1e2 100644
> --- a/drivers/gpu/drm/gma500/fbdev.c
> +++ b/drivers/gpu/drm/gma500/fbdev.c
> @@ -84,9 +84,6 @@ static void psb_fbdev_fb_destroy(struct fb_info *info)
>   	drm_gem_object_put(obj);
>   
>   	drm_client_release(&fb_helper->client);
> -
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops psb_fbdev_fb_ops = {
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index 3fbdf75415cc..d5f26c8bb102 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -146,8 +146,6 @@ static void intel_fbdev_fb_destroy(struct fb_info *info)
>   	drm_framebuffer_remove(fb_helper->fb);
>   
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   __diag_push();
> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
> index b5969374d53f..aad6fb77f0de 100644
> --- a/drivers/gpu/drm/msm/msm_fbdev.c
> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
> @@ -52,8 +52,6 @@ static void msm_fbdev_fb_destroy(struct fb_info *info)
>   	drm_framebuffer_remove(fb);
>   
>   	drm_client_release(&helper->client);
> -	drm_fb_helper_unprepare(helper);
> -	kfree(helper);
>   }
>   
>   static const struct fb_ops msm_fb_ops = {
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index 948af7ec1130..b5df2923d2a6 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -103,8 +103,6 @@ static void omap_fbdev_fb_destroy(struct fb_info *info)
>   	drm_framebuffer_remove(fb);
>   
>   	drm_client_release(&helper->client);
> -	drm_fb_helper_unprepare(helper);
> -	kfree(helper);
>   }
>   
>   /*
> diff --git a/drivers/gpu/drm/radeon/radeon_fbdev.c b/drivers/gpu/drm/radeon/radeon_fbdev.c
> index dc81b0c2dbff..4df6c9167bf0 100644
> --- a/drivers/gpu/drm/radeon/radeon_fbdev.c
> +++ b/drivers/gpu/drm/radeon/radeon_fbdev.c
> @@ -184,8 +184,6 @@ static void radeon_fbdev_fb_destroy(struct fb_info *info)
>   	radeon_fbdev_destroy_pinned_object(gobj);
>   
>   	drm_client_release(&fb_helper->client);
> -	drm_fb_helper_unprepare(fb_helper);
> -	kfree(fb_helper);
>   }
>   
>   static const struct fb_ops radeon_fbdev_fb_ops = {
> diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
> index 1b70f5e164af..91aece6f34e0 100644
> --- a/drivers/gpu/drm/tegra/fbdev.c
> +++ b/drivers/gpu/drm/tegra/fbdev.c
> @@ -53,8 +53,6 @@ static void tegra_fbdev_fb_destroy(struct fb_info *info)
>   	drm_framebuffer_remove(fb);
>   
>   	drm_client_release(&helper->client);
> -	drm_fb_helper_unprepare(helper);
> -	kfree(helper);
>   }
>   
>   static const struct fb_ops tegra_fb_ops = {
> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
> index bdd845e383ef..eecb8d6e15c7 100644
> --- a/include/drm/drm_client.h
> +++ b/include/drm/drm_client.h
> @@ -28,6 +28,16 @@ struct drm_client_funcs {
>   	 */
>   	struct module *owner;
>   
> +	/**
> +	 * @free:
> +	 *
> +	 * Called when the client gets unregistered. Implementations should
> +	 * release all client-specific data and free the memory.
> +	 *
> +	 * This callback is optional.
> +	 */
> +	void (*free)(struct drm_client_dev *client);
> +
>   	/**
>   	 * @unregister:
>   	 *

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)