Re: [PATCH v2 5/8] drm/gm12u320: replace struct drm_simple_display_pipe with regular atomic helpers
From: Thomas Zimmermann
Date: Fri Jul 17 2026 - 03:19:03 EST
Hi
Am 16.07.26 um 11:01 schrieb Ze Huang:
Convert gm12u320 to direct primary plane, CRTC and encoder setup.[...]
Keep shadow-plane helper state, framebuffer access helpers and
no-scaling plane-state check from simple-KMS path.
Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Tested-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Signed-off-by: Ze Huang <ze.huang@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/tiny/gm12u320.c | 132 ++++++++++++++++++++++++++++++++--------
1 file changed, 107 insertions(+), 25 deletions(-)
-static void gm12u320_pipe_enable(struct drm_simple_display_pipe *pipe,
- struct drm_crtc_state *crtc_state,
- struct drm_plane_state *plane_state)
+static void gm12u320_crtc_helper_atomic_enable(struct drm_crtc *crtc,
+ struct drm_atomic_commit *commit)
{
struct drm_rect rect = { 0, 0, GM12U320_USER_WIDTH, GM12U320_HEIGHT };
- struct gm12u320_device *gm12u320 = to_gm12u320(pipe->crtc.dev);
+ struct gm12u320_device *gm12u320 = to_gm12u320(crtc->dev);
+ struct drm_plane_state *plane_state = gm12u320->plane.state;
Did you see the reply from the Sashiko bot?
What happens is that user space can apply multiple atomic commits in a row, but they are applied to hardware asynchronously. So if you take the plane state here directly from the plane, it could have been replaced by a later atomic commit already. Rather get the correct plane state with the helper drm_atomic_get_new_plane_state(). I did not look at all of the series' patches for this problem, but the rule applies to all of the mode-setting code. Best regards Thomas
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
gm12u320->fb_update.draw_status_timeout = FIRST_FRAME_TIMEOUT;
gm12u320_fb_mark_dirty(plane_state->fb, &shadow_plane_state->data[0], &rect);
}
-static void gm12u320_pipe_disable(struct drm_simple_display_pipe *pipe)
+static void gm12u320_crtc_helper_atomic_disable(struct drm_crtc *crtc,
+ struct drm_atomic_commit *commit)
{
- struct gm12u320_device *gm12u320 = to_gm12u320(pipe->crtc.dev);
+ struct gm12u320_device *gm12u320 = to_gm12u320(crtc->dev);
gm12u320_stop_fb_update(gm12u320);
}
-static void gm12u320_pipe_update(struct drm_simple_display_pipe *pipe,
- struct drm_plane_state *old_state)
+static void gm12u320_plane_helper_atomic_update(struct drm_plane *plane,
+ struct drm_atomic_commit *commit)
{
- struct drm_plane_state *state = pipe->plane.state;
+ struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(commit, plane);
+ struct drm_plane_state *state = drm_atomic_get_new_plane_state(commit, plane);
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
struct drm_rect rect;
+ if (!state->fb)
+ return;
+
if (drm_atomic_helper_damage_merged(old_state, state, &rect))
gm12u320_fb_mark_dirty(state->fb, &shadow_plane_state->data[0], &rect);
}
-static const struct drm_simple_display_pipe_funcs gm12u320_pipe_funcs = {
- .enable = gm12u320_pipe_enable,
- .disable = gm12u320_pipe_disable,
- .update = gm12u320_pipe_update,
- DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
+static const struct drm_plane_funcs gm12u320_plane_funcs = {
+ .update_plane = drm_atomic_helper_update_plane,
+ .disable_plane = drm_atomic_helper_disable_plane,
+ .destroy = drm_plane_cleanup,
+ DRM_GEM_SHADOW_PLANE_FUNCS,
+};
+
+static int gm12u320_plane_helper_atomic_check(struct drm_plane *plane,
+ struct drm_atomic_commit *commit)
+{
+ struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(commit, plane);
+ struct drm_crtc *crtc = plane_state->crtc;
+ struct drm_crtc_state *crtc_state = NULL;
+
+ if (crtc)
+ crtc_state = drm_atomic_get_new_crtc_state(commit, crtc);
+
+ return drm_atomic_helper_check_plane_state(plane_state, crtc_state,
+ DRM_PLANE_NO_SCALING,
+ DRM_PLANE_NO_SCALING,
+ false, false);
+}
+
+static const struct drm_plane_helper_funcs gm12u320_plane_helper_funcs = {
+ DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+ .atomic_check = gm12u320_plane_helper_atomic_check,
+ .atomic_update = gm12u320_plane_helper_atomic_update,
+};
+
+static int gm12u320_crtc_helper_atomic_check(struct drm_crtc *crtc,
+ struct drm_atomic_commit *commit)
+{
+ struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(commit, crtc);
+ int ret;
+
+ if (crtc_state->enable) {
+ ret = drm_atomic_helper_check_crtc_primary_plane(crtc_state);
+ if (ret)
+ return ret;
+ }
+
+ return drm_atomic_add_affected_planes(commit, crtc);
+}
+
+static const struct drm_crtc_helper_funcs gm12u320_crtc_helper_funcs = {
+ .atomic_check = gm12u320_crtc_helper_atomic_check,
+ .atomic_enable = gm12u320_crtc_helper_atomic_enable,
+ .atomic_disable = gm12u320_crtc_helper_atomic_disable,
+};
+
+static const struct drm_crtc_funcs gm12u320_crtc_funcs = {
+ .set_config = drm_atomic_helper_set_config,
+ .page_flip = drm_atomic_helper_page_flip,
+ .reset = drm_atomic_helper_crtc_reset,
+ .destroy = drm_crtc_cleanup,
+ .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+};
+
+static const struct drm_encoder_funcs gm12u320_encoder_funcs = {
+ .destroy = drm_encoder_cleanup,
};
static const uint32_t gm12u320_pipe_formats[] = {
@@ -677,13 +743,29 @@ static int gm12u320_usb_probe(struct usb_interface *interface,
if (ret)
return ret;
- ret = drm_simple_display_pipe_init(&gm12u320->dev,
- &gm12u320->pipe,
- &gm12u320_pipe_funcs,
- gm12u320_pipe_formats,
- ARRAY_SIZE(gm12u320_pipe_formats),
- gm12u320_pipe_modifiers,
- &gm12u320->conn);
+ ret = drm_universal_plane_init(dev, &gm12u320->plane, 0,
+ &gm12u320_plane_funcs,
+ gm12u320_pipe_formats,
+ ARRAY_SIZE(gm12u320_pipe_formats),
+ gm12u320_pipe_modifiers,
+ DRM_PLANE_TYPE_PRIMARY, NULL);
+ if (ret)
+ return ret;
+ drm_plane_helper_add(&gm12u320->plane, &gm12u320_plane_helper_funcs);
+
+ ret = drm_crtc_init_with_planes(dev, &gm12u320->crtc, &gm12u320->plane, NULL,
+ &gm12u320_crtc_funcs, NULL);
+ if (ret)
+ return ret;
+ drm_crtc_helper_add(&gm12u320->crtc, &gm12u320_crtc_helper_funcs);
+
+ ret = drm_encoder_init(dev, &gm12u320->encoder, &gm12u320_encoder_funcs,
+ DRM_MODE_ENCODER_NONE, NULL);
+ if (ret)
+ return ret;
+ gm12u320->encoder.possible_crtcs = drm_crtc_mask(&gm12u320->crtc);
+
+ ret = drm_connector_attach_encoder(&gm12u320->conn, &gm12u320->encoder);
if (ret)
return ret;
--
--
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)