Hi Maxime
Am 09.07.26 um 13:50 schrieb Maxime Ripard:
The simple-kms helper provides a reset_plane hook to let drivers
override the default plane reset. However, the reset hook is
overloaded: it is used to create the initial software state at probe
time, but also to reset both the hardware and software state during
suspend/resume. These two roles have different expectations, and
reset is not fallible which makes error handling difficult.
The atomic_create_state pattern was introduced to untangle this by
providing a hook that only allocates and initializes a pristine state
without any side effect.
Add a create_plane_state hook to struct
drm_simple_display_pipe_funcs. When provided,
drm_simple_kms_plane_reset() will use it to allocate a fresh state,
falling back to reset_plane and then to the default
drm_atomic_helper_plane_reset().
This will allow simple-kms drivers to be converted to the
atomic_create_state pattern.
Have you seen
https://lore.kernel.org/dri-devel/20260705-drm-simple-kms-removal-v1-0-b4e1ca053...@oss.qualcomm.com/
? Once this lands, simple-kms will have no users left and be gone soon
after.
I assume that creating that new callback here is the easiest way forward
for atomic_create_state?
Best regards
Thomas
Signed-off-by: Maxime Ripard <[email protected]>
---
drivers/gpu/drm/drm_simple_kms_helper.c | 23 +++++++++++++++++++++--
include/drm/drm_simple_kms_helper.h | 1 +
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c
b/drivers/gpu/drm/drm_simple_kms_helper.c
index 8e1d07b9f1e3..efb643ab6448 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -284,14 +284,33 @@ static const struct drm_plane_helper_funcs
drm_simple_kms_plane_helper_funcs = {
static void drm_simple_kms_plane_reset(struct drm_plane *plane)
{
struct drm_simple_display_pipe *pipe;
pipe = container_of(plane, struct drm_simple_display_pipe, plane);
- if (!pipe->funcs || !pipe->funcs->reset_plane)
+ if (!pipe->funcs)
return drm_atomic_helper_plane_reset(plane);
- return pipe->funcs->reset_plane(pipe);
+ if (pipe->funcs->reset_plane)
+ return pipe->funcs->reset_plane(pipe);
+
+ if (pipe->funcs->create_plane_state) {
+ struct drm_plane_state *state;
+
+ if (plane->state) {
+ pipe->funcs->destroy_plane_state(pipe, plane->state);
+ plane->state = NULL;
+ }
+
+ state = pipe->funcs->create_plane_state(pipe);
+ if (WARN_ON(IS_ERR(state)))
+ return;
+
+ plane->state = state;
+ return;
+ }
+
+ return drm_atomic_helper_plane_reset(plane);
}
static struct drm_plane_state *drm_simple_kms_plane_duplicate_state(struct drm_plane *plane)
{
struct drm_simple_display_pipe *pipe;
diff --git a/include/drm/drm_simple_kms_helper.h
b/include/drm/drm_simple_kms_helper.h
index cb672ce0e856..b58f6d532820 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -42,10 +42,11 @@ struct drm_simple_display_pipe_funcs {
void (*reset_crtc)(struct drm_simple_display_pipe *pipe);
struct drm_crtc_state * (*duplicate_crtc_state)(struct
drm_simple_display_pipe *pipe);
void (*destroy_crtc_state)(struct drm_simple_display_pipe *pipe,
struct drm_crtc_state *crtc_state);
void (*reset_plane)(struct drm_simple_display_pipe *pipe);
+ struct drm_plane_state * (*create_plane_state)(struct
drm_simple_display_pipe *pipe);
struct drm_plane_state * (*duplicate_plane_state)(struct
drm_simple_display_pipe *pipe);
void (*destroy_plane_state)(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state);
};
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)
