linux-kernel - Re: [PATCH v2 2/8] drm/rockchip: vop2: Switch impossible pos conditional to WARN

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Message-ID: <956a5ead-cc3b-41de-8431-2f03aaee3c71@suse.de>
Date: Tue, 20 Jan 2026 13:52:30 +0100
From: Thomas Zimmermann <tzimmermann@...e.de>
To: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>,
 Sandy Huang <hjc@...k-chips.com>, Heiko Stübner
 <heiko@...ech.de>, Andy Yan <andy.yan@...k-chips.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>
Cc: kernel@...labora.com, dri-devel@...ts.freedesktop.org,
 linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
 linux-kernel@...r.kernel.org, Daniel Stone <daniels@...labora.com>
Subject: Re: [PATCH v2 2/8] drm/rockchip: vop2: Switch impossible pos
 conditional to WARN_ON

Hi

Am 06.12.25 um 21:45 schrieb Nicolas Frattaroli:
> From: Daniel Stone <daniels@...labora.com>
>
> We already clip the plane to the display bounds in atomic_check, and
> ensure that it is sufficiently sized. Instead of trying to catch this
> and adjust for it in atomic_update, just assert that atomic_check has
> done its job.
>
> Signed-off-by: Daniel Stone <daniels@...labora.com>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
> ---
>   drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 29 +++++++++-------------------
>   1 file changed, 9 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> index 20b49209ddcd..81b3eba07095 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> @@ -1214,28 +1214,17 @@ static void vop2_plane_atomic_update(struct drm_plane *plane,
>   	src_w = drm_rect_width(src) >> 16;
>   	src_h = drm_rect_height(src) >> 16;
>   	dsp_w = drm_rect_width(dest);
> -
> -	if (dest->x1 + dsp_w > adjusted_mode->hdisplay) {
> -		drm_dbg_kms(vop2->drm,
> -			    "vp%d %s dest->x1[%d] + dsp_w[%d] exceed mode hdisplay[%d]\n",
> -			    vp->id, win->data->name, dest->x1, dsp_w, adjusted_mode->hdisplay);
> -		dsp_w = adjusted_mode->hdisplay - dest->x1;
> -		if (dsp_w < 4)
> -			dsp_w = 4;
> -		src_w = dsp_w * src_w / drm_rect_width(dest);
> -	}
> -
>   	dsp_h = drm_rect_height(dest);
>   
> -	if (dest->y1 + dsp_h > adjusted_mode->vdisplay) {
> -		drm_dbg_kms(vop2->drm,
> -			    "vp%d %s dest->y1[%d] + dsp_h[%d] exceed mode vdisplay[%d]\n",
> -			    vp->id, win->data->name, dest->y1, dsp_h, adjusted_mode->vdisplay);
> -		dsp_h = adjusted_mode->vdisplay - dest->y1;
> -		if (dsp_h < 4)
> -			dsp_h = 4;
> -		src_h = dsp_h * src_h / drm_rect_height(dest);
> -	}
> +	/* drm_atomic_helper_check_plane_state calls drm_rect_clip_scaled for
> +	 * us, which keeps our planes bounded within the CRTC active area
> +	 */
> +	WARN_ON(dest->x1 + dsp_w > adjusted_mode->hdisplay);
> +	WARN_ON(dest->y1 + dsp_h > adjusted_mode->vdisplay);
> +	WARN_ON(dsp_w < 4);
> +	WARN_ON(dsp_h < 4);
> +	WARN_ON(src_w < 4);
> +	WARN_ON(src_h < 4);

This should also use drm_WARN_ON().  But maybe rather leave it out 
entirely? I don't remember having seen other drivers to re-test in 
atomic_update.

Best regards
Thomas


>   
>   	/*
>   	 * This is workaround solution for IC design:
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)