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[v5,05/19] drm/mode-config: Document drm_private_obj exclusion from drm_mode_config_reset()

Message ID 20260519-drm-mode-config-init-v5-5-388b03321e38@kernel.org (mailing list archive)
State New
Headers
Series drm/atomic: Rework initial state allocation |

Commit Message

Maxime Ripard May 19, 2026, 9:01 a.m. UTC 
drm_mode_config_reset() does not reset drm_private_states by design.

This is especially significant for the DP MST and tunneling code that
expect to be preserved across a suspend/resume cycle, where
drm_mode_config_reset() is also used.

Document this expectation.

Link: https://lore.kernel.org/dri-devel/aOaQLx-7EpsHRwkH@ideak-desk/
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/drm_mode_config.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Thomas Zimmermann May 26, 2026, 9:05 a.m. UTC | #1 
Am 19.05.26 um 11:01 schrieb Maxime Ripard:
> drm_mode_config_reset() does not reset drm_private_states by design.
>
> This is especially significant for the DP MST and tunneling code that
> expect to be preserved across a suspend/resume cycle, where
> drm_mode_config_reset() is also used.
>
> Document this expectation.
>
> Link: https://lore.kernel.org/dri-devel/aOaQLx-7EpsHRwkH@ideak-desk/
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Signed-off-by: Maxime Ripard <mripard@kernel.org>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
>   drivers/gpu/drm/drm_mode_config.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index 66f7dc37b597..c33382a38191 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -187,10 +187,14 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
>    * @dev: drm device
>    *
>    * This functions calls all the crtc's, encoder's and connector's ->reset
>    * callback. Drivers can use this in e.g. their driver load or resume code to
>    * reset hardware and software state.
> + *
> + * Note that &drm_private_obj structures are expected to be stable across
> + * suspend/resume cycles, and drm_mode_config_reset() does not affect these
> + * structures.
>    */
>   void drm_mode_config_reset(struct drm_device *dev)
>   {
>   	struct drm_crtc *crtc;
>   	struct drm_colorop *colorop;
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 66f7dc37b597..c33382a38191 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -187,10 +187,14 @@  int drm_mode_getresources(struct drm_device *dev, void *data,
  * @dev: drm device
  *
  * This functions calls all the crtc's, encoder's and connector's ->reset
  * callback. Drivers can use this in e.g. their driver load or resume code to
  * reset hardware and software state.
+ *
+ * Note that &drm_private_obj structures are expected to be stable across
+ * suspend/resume cycles, and drm_mode_config_reset() does not affect these
+ * structures.
  */
 void drm_mode_config_reset(struct drm_device *dev)
 {
 	struct drm_crtc *crtc;
 	struct drm_colorop *colorop;