Hi Maxime,
Thank you for the patch.
On Tue, Sep 02, 2025 at 10:32:35AM +0200, Maxime Ripard wrote:
> We currently have a helper to print the new states associated to a
> drm_atomic_state, but we don't have a variant to print the old state.
>
> It's somewhat expected, since we almost never care about what the new
> state looks like when we commit a new state, but we're about to change
> that.
>
> Signed-off-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> drivers/gpu/drm/drm_atomic.c | 45 +++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/drm_crtc_internal.h | 2 ++
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 9b198610791d19c7fd276ca59264a961d21caf43..38f2b2633fa992b3543e8c425c7faeab1ce69765 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1875,10 +1875,55 @@ void drm_atomic_print_new_state(const struct drm_atomic_state *state,
> for_each_new_private_obj_in_state(state, obj, obj_state, i)
> drm_atomic_private_obj_print_state(p, obj_state);
> }
> EXPORT_SYMBOL(drm_atomic_print_new_state);
>
> +/**
> + * drm_atomic_print_old_state - prints drm atomic state
> + * @state: atomic configuration to check
> + * @p: drm printer
> + *
> + * This functions prints the drm atomic state snapshot using the drm printer
> + * which is passed to it. This snapshot can be used for debugging purposes.
> + *
> + * Note that this function looks into the old state objects and hence its not
> + * safe to be used after the call to drm_atomic_helper_commit_hw_done().
> + */
> +void drm_atomic_print_old_state(const struct drm_atomic_state *state,
> + struct drm_printer *p)
> +{
> + struct drm_plane *plane;
> + struct drm_plane_state *plane_state;
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *crtc_state;
> + struct drm_connector *connector;
> + struct drm_connector_state *connector_state;
> + struct drm_private_obj *obj;
> + struct drm_private_state *obj_state;
> + int i;
> +
> + if (!p) {
> + drm_err(state->dev, "invalid drm printer\n");
> + return;
> + }
> +
> + drm_dbg_atomic(state->dev, "checking %p\n", state);
> +
> + for_each_old_plane_in_state(state, plane, plane_state, i)
> + drm_atomic_plane_print_state(p, plane_state);
> +
> + for_each_old_crtc_in_state(state, crtc, crtc_state, i)
> + drm_atomic_crtc_print_state(p, crtc_state);
> +
> + for_each_old_connector_in_state(state, connector, connector_state, i)
> + drm_atomic_connector_print_state(p, connector_state);
> +
> + for_each_old_private_obj_in_state(state, obj, obj_state, i)
> + drm_atomic_private_obj_print_state(p, obj_state);
> +}
> +EXPORT_SYMBOL(drm_atomic_print_old_state);
> +
> static void __drm_state_dump(struct drm_device *dev, struct drm_printer *p,
> bool take_locks)
> {
> struct drm_mode_config *config = &dev->mode_config;
> struct drm_plane *plane;
> diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
> index 89706aa8232fc0b2830af67c7588985a29653299..a8139fda1a1015c2ac8d8af3b12c5ac0b00cfc1a 100644
> --- a/drivers/gpu/drm/drm_crtc_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_internal.h
> @@ -249,10 +249,12 @@ int __drm_atomic_helper_disable_plane(struct drm_plane *plane,
> int __drm_atomic_helper_set_config(struct drm_mode_set *set,
> struct drm_atomic_state *state);
>
> void drm_atomic_print_new_state(const struct drm_atomic_state *state,
> struct drm_printer *p);
> +void drm_atomic_print_old_state(const struct drm_atomic_state *state,
> + struct drm_printer *p);
>
> /* drm_atomic_uapi.c */
> int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state,
> struct drm_connector *connector,
> int mode);
--
Regards,
Laurent Pinchart