[PATCH] drm/sysfb: Clear entire framebuffer in atomic_disable

From: oushixiong1025

Date: Wed Aug 26 2026 - 03:59:20 EST


From: Shixiong Ou <oushixiong@xxxxxxxxxx>

drm_sysfb_plane_helper_atomic_disable() previously used
plane_state->src_* coordinates to construct the clear rectangle,
which depends on user-controlled input. Instead, clear the entire
visible framebuffer region using fb_mode dimensions, and use
drm_format_info_min_pitch() to compute the safe per-line clear size
without touching non-visible bytes at the end of each line.

Signed-off-by: Shixiong Ou <oushixiong@xxxxxxxxxx>
---
drivers/gpu/drm/sysfb/drm_sysfb_modeset.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c b/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
index 9a4c210d6f96..c109ecab9d7a 100644
--- a/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_modeset.c
@@ -376,28 +376,28 @@ void drm_sysfb_plane_helper_atomic_disable(struct drm_plane *plane,
struct drm_device *dev = plane->dev;
struct drm_sysfb_device *sysfb = to_drm_sysfb_device(dev);
struct iosys_map dst = sysfb->fb_addr;
- struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
void __iomem *dst_vmap = dst.vaddr_iomem; /* TODO: Use mapping abstraction */
unsigned int dst_pitch = sysfb->fb_pitch;
const struct drm_format_info *dst_format = sysfb->fb_format;
struct drm_rect dst_clip;
- unsigned long lines, linepixels, i;
+ unsigned long lines, linepixels, dst_size, i;
int idx;

- drm_rect_init(&dst_clip,
- plane_state->src_x >> 16, plane_state->src_y >> 16,
- plane_state->src_w >> 16, plane_state->src_h >> 16);
+ drm_rect_init(&dst_clip, 0, 0,
+ sysfb->fb_mode.hdisplay, sysfb->fb_mode.vdisplay);

lines = drm_rect_height(&dst_clip);
linepixels = drm_rect_width(&dst_clip);
+ dst_size = min_t(unsigned long,
+ drm_format_info_min_pitch(dst_format, 0, linepixels),
+ dst_pitch);

if (!drm_dev_enter(dev, &idx))
return;

/* Clear buffer to black if disabled */
- dst_vmap += drm_fb_clip_offset(dst_pitch, dst_format, &dst_clip);
for (i = 0; i < lines; ++i) {
- memset_io(dst_vmap, 0, linepixels * dst_format->cpp[0]);
+ memset_io(dst_vmap, 0, dst_size);
dst_vmap += dst_pitch;
}

--
2.25.1