Almost all drivers, and our documented skeleton, call
drm_mode_config_reset() prior to calling drm_dev_register() to
initialize its DRM object states.

Now that we have drm_mode_config_create_state() to create that initial
state if it doesn't exist, we can call it directly in
drm_dev_register(). That way, we know that the initial atomic state will
always be allocated without any boilerplate.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/drm_drv.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 2915118436ce8a6640cfb0c59936031990727ed1..820106d56ab399a39cac56d98662b5ddbcae8ded 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -1097,10 +1097,14 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		ret = drm_modeset_register_all(dev);
 		if (ret)
 			goto err_unload;
+
+		ret = drm_mode_config_create_state(dev);
+		if (ret)
+			goto err_unload;
 	}
 	drm_panic_register(dev);
 	drm_client_sysrq_register(dev);
 
 	DRM_INFO("Initialized %s %d.%d.%d for %s on minor %d\n",

-- 
2.53.0

On Tue, Mar 10, 2026 at 05:07:01PM +0100, Maxime Ripard wrote:
> Almost all drivers, and our documented skeleton, call
> drm_mode_config_reset() prior to calling drm_dev_register() to
> initialize its DRM object states.
> 
> Now that we have drm_mode_config_create_state() to create that initial
> state if it doesn't exist, we can call it directly in
> drm_dev_register(). That way, we know that the initial atomic state will
> always be allocated without any boilerplate.

Should most drivers now stop calling drm_mode_config_reset() at probe
time ?

> Signed-off-by: Maxime Ripard <mripard@kernel.org>
> ---
>  drivers/gpu/drm/drm_drv.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 2915118436ce8a6640cfb0c59936031990727ed1..820106d56ab399a39cac56d98662b5ddbcae8ded 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -1097,10 +1097,14 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
>  
>  	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
>  		ret = drm_modeset_register_all(dev);
>  		if (ret)
>  			goto err_unload;
> +
> +		ret = drm_mode_config_create_state(dev);
> +		if (ret)
> +			goto err_unload;
>  	}
>  	drm_panic_register(dev);
>  	drm_client_sysrq_register(dev);
>  
>  	DRM_INFO("Initialized %s %d.%d.%d for %s on minor %d\n",

-- 
Regards,

Laurent Pinchart

On Mon, Mar 16, 2026 at 06:33:54PM +0200, Laurent Pinchart wrote:
> On Tue, Mar 10, 2026 at 05:07:01PM +0100, Maxime Ripard wrote:
> > Almost all drivers, and our documented skeleton, call
> > drm_mode_config_reset() prior to calling drm_dev_register() to
> > initialize its DRM object states.
> > 
> > Now that we have drm_mode_config_create_state() to create that initial
> > state if it doesn't exist, we can call it directly in
> > drm_dev_register(). That way, we know that the initial atomic state will
> > always be allocated without any boilerplate.
> 
> Should most drivers now stop calling drm_mode_config_reset() at probe
> time ?

Yes, that's my intention. For the vast majority of them, reset is just
about allocating and committing a blank state anyway.

However, for the drivers that do need to reset the hardware, we should
keep the door open (and / or provide an alternative mechanism).

Maxime