[PATCH 6.18 178/752] drm/atmel-hlcdc: don't reject the commit if the src rect has fractional parts

Sasha Levin
2026-02-28T17:50:40Z

From: Ludovic Desroches <ludovic.desroches@microchip.com>

[ Upstream commit 06682206e2a1883354ed758c09efeb51f435adbd ]

Don’t reject the commit when the source rectangle has fractional parts.
This can occur due to scaling: drm_atomic_helper_check_plane_state() calls
drm_rect_clip_scaled(), which may introduce fractional parts while
computing the clipped source rectangle. This does not imply the commit is
invalid, so we should accept it instead of discarding it.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Link: https://patch.msgid.link/20251120-lcd_scaling_fix-v1-1-5ffc98557923@microchip.com
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index 410ec747cc7e0..caf6deda717ce 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -78,8 +78,6 @@ drm_plane_state_to_atmel_hlcdc_plane_state(struct drm_plane_state *s)
return container_of(s, struct atmel_hlcdc_plane_state, base);
}

-#define SUBPIXEL_MASK 0xffff
-
static uint32_t rgb_formats[] = {
DRM_FORMAT_C8,
DRM_FORMAT_XRGB4444,
@@ -744,24 +742,15 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
if (ret || !s->visible)
return ret;

- hstate->src_x = s->src.x1;
- hstate->src_y = s->src.y1;
- hstate->src_w = drm_rect_width(&s->src);
- hstate->src_h = drm_rect_height(&s->src);
+ hstate->src_x = s->src.x1 >> 16;
+ hstate->src_y = s->src.y1 >> 16;
+ hstate->src_w = drm_rect_width(&s->src) >> 16;
+ hstate->src_h = drm_rect_height(&s->src) >> 16;
hstate->crtc_x = s->dst.x1;
hstate->crtc_y = s->dst.y1;
hstate->crtc_w = drm_rect_width(&s->dst);
hstate->crtc_h = drm_rect_height(&s->dst);

- if ((hstate->src_x | hstate->src_y | hstate->src_w | hstate->src_h) &
- SUBPIXEL_MASK)
- return -EINVAL;
-
- hstate->src_x >>= 16;
- hstate->src_y >>= 16;
- hstate->src_w >>= 16;
- hstate->src_h >>= 16;
-
hstate->nplanes = fb->format->num_planes;
if (hstate->nplanes > ATMEL_HLCDC_LAYER_MAX_PLANES)
return -EINVAL;
--
2.51.0