linux-kernel - Re: [PATCH] drm/atmel-hlcdc: don't reject the commit if the src rect has fractional parts

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Message-ID: <43c48e38-021e-4e3a-b872-b89c90108b54@microchip.com>
Date: Mon, 5 Jan 2026 07:06:46 +0000
From: <Manikandan.M@...rochip.com>
To: <Ludovic.Desroches@...rochip.com>, <Dharma.B@...rochip.com>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <simona@...ll.ch>,
	<Nicolas.Ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
	<claudiu.beznea@...on.dev>
CC: <dri-devel@...ts.freedesktop.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/atmel-hlcdc: don't reject the commit if the src rect
 has fractional parts

On 20/11/25 4:08 pm, Ludovic Desroches wrote:
> 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@...rochip.com>

Reviewed-by: Manikandan Muralidharan <manikandan.m@...rochip.com>

Thanks Ludovic.
> ---
>   drivers/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 92132be9823f1e705d266f9547702ea9530bd043..bccfe055c087e5632d60503e8e4bcb3d9e18ce50 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> @@ -79,8 +79,6 @@ 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,
> @@ -745,24 +743,15 @@ 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;
> 
> ---
> base-commit: fe4d0dea039f2befb93f27569593ec209843b0f5
> change-id: 20251119-lcd_scaling_fix-a4842d86307c
> 
> Best regards,

-- 
Thanks and Regards,
Manikandan M.