[PATCH v3 05/10] drm/appletbdrm: Allocate request/response buffers in begin_fb_access
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: 2026-05-27 14:51:40
Also in:
dri-devel, intel-gfx, intel-xe, linux-mips, virtualization
Subsystem:
drm driver for apple touch bars, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
Aun-Ali Zaidi, Aditya Garg, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
In atomic_check, damage handling is not fully evaluated. Another atomic_check helper could trigger a full modeset and thus invalidate damage clips. Allocation of the request/response buffers in appletbdrm depends on correct damage information. Otherwise it might allocate incorrectly sized buffers. Allocate the buffers in the driver's begin_fb_access helper. It runs early during the commit when damage clipping has been fully evaluated. v2: - allocate before drm_gem_begin_shadow_fb_access() to avoid leak on error Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Aditya Garg <redacted> --- drivers/gpu/drm/tiny/appletbdrm.c | 53 +++++++++++++++++-------------- 1 file changed, 30 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
index cdd35af49892..b683dcb35b0b 100644
--- a/drivers/gpu/drm/tiny/appletbdrm.c
+++ b/drivers/gpu/drm/tiny/appletbdrm.c@@ -315,33 +315,16 @@ static const u32 appletbdrm_primary_plane_formats[] = { DRM_FORMAT_XRGB8888, /* emulated */ }; -static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane, - struct drm_atomic_commit *state) +static int appletbdrm_primary_plane_helper_begin_fb_access(struct drm_plane *plane, + struct drm_plane_state *new_plane_state) { - struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane); - struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane); - struct drm_crtc *new_crtc = new_plane_state->crtc; - struct drm_crtc_state *new_crtc_state = NULL; struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state); + size_t frames_size = 0; struct drm_atomic_helper_damage_iter iter; struct drm_rect damage; - size_t frames_size = 0; size_t request_size; - int ret; - - if (new_crtc) - new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc); - ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state, - DRM_PLANE_NO_SCALING, - DRM_PLANE_NO_SCALING, - false, false); - if (ret) - return ret; - else if (!new_plane_state->visible) - return 0; - - drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state); + drm_atomic_helper_damage_iter_init(&iter, NULL, new_plane_state); drm_atomic_for_each_plane_damage(&iter, &damage) { frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage)); }
@@ -366,6 +349,29 @@ static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane, appletbdrm_state->request_size = request_size; appletbdrm_state->frames_size = frames_size; + return drm_gem_begin_shadow_fb_access(plane, new_plane_state); +} + +static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane, + struct drm_atomic_commit *state) +{ + struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane); + struct drm_crtc *new_crtc = new_plane_state->crtc; + struct drm_crtc_state *new_crtc_state = NULL; + int ret; + + if (new_crtc) + new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc); + + ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state, + DRM_PLANE_NO_SCALING, + DRM_PLANE_NO_SCALING, + false, false); + if (ret) + return ret; + else if (!new_plane_state->visible) + return 0; + return 0; }
@@ -468,7 +474,7 @@ static int appletbdrm_flush_damage(struct appletbdrm_device *adev, } static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane, - struct drm_atomic_commit *old_state) + struct drm_atomic_commit *old_state) { struct appletbdrm_device *adev = drm_to_adev(plane->dev); struct drm_device *drm = plane->dev;
@@ -552,7 +558,8 @@ static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane, } static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = { - DRM_GEM_SHADOW_PLANE_HELPER_FUNCS, + .begin_fb_access = appletbdrm_primary_plane_helper_begin_fb_access, + .end_fb_access = drm_gem_end_shadow_fb_access, .atomic_check = appletbdrm_primary_plane_helper_atomic_check, .atomic_update = appletbdrm_primary_plane_helper_atomic_update, .atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
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2.54.0