Re:[PATCH 2/2] drm/rockchip: dw_hdmi_qp: expose "overscan" property

From: "Andy Yan" <andyshrk@163•com>
To: "Alexey Charkov" <alchark@flipper•net>
Cc: "Sandy Huang" <hjc@rock-chips•com>,
	"Heiko Stübner" <heiko@sntech•de>,
	"Andy Yan" <andy.yan@rock-chips•com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux•intel.com>,
	"Maxime Ripard" <mripard@kernel•org>,
	"Thomas Zimmermann" <tzimmermann@suse•de>,
	"David Airlie" <airlied@gmail•com>,
	"Simona Vetter" <simona@ffwll•ch>,
	"Cristian Ciocaltea" <cristian.ciocaltea@collabora•com>,
	dri-devel@lists•freedesktop.org,
	linux-arm-kernel@lists•infradead.org,
	linux-rockchip@lists•infradead.org, linux-kernel@vger•kernel.org
Subject: Re:[PATCH 2/2] drm/rockchip: dw_hdmi_qp: expose "overscan" property
Date: Wed, 3 Jun 2026 21:11:05 +0800 (CST)	[thread overview]
Message-ID: <6f7ae6e2.a68c.19e8d9be74d.Coremail.andyshrk@163.com> (raw)
In-Reply-To: <20260602-hdmi-overscan-v1-2-31f71b817c80@flipper.net>


Hello Alexy，

At 2026-06-03 01:00:40, "Alexey Charkov" <alchark@flipper•net> wrote:
>Expose the "overscan" connector property as recognized by KWin and the
>likes to compensate for TV overscan cropping.
>
>The CRTC will use the margin values derived from this overscan percentage
>in its post-composition scaler to add appropriate blank margins on all
>sides of the output image so that the TV doesn't eat up visible content.
>
>Signed-off-by: Alexey Charkov <alchark@flipper•net>
>---
> drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
>diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>index f35484715c2d..fae44d11dbef 100644
>--- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>+++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
>@@ -137,10 +137,18 @@ dw_hdmi_qp_rockchip_encoder_atomic_check(struct drm_encoder *encoder,
> 					 struct drm_connector_state *conn_state)
> {
> 	struct rockchip_hdmi_qp *hdmi = to_rockchip_hdmi_qp(encoder);
>+	const struct drm_display_mode *adj_mode = &crtc_state->adjusted_mode;
> 	struct rockchip_crtc_state *s = to_rockchip_crtc_state(crtc_state);
> 	union phy_configure_opts phy_cfg = {};
>+	unsigned int overscan;
> 	int ret;
> 
>+	overscan = min(conn_state->tv.overscan, 100u);
>+	s->tv_margins.left   = adj_mode->hdisplay * overscan / 200;
>+	s->tv_margins.right  = s->tv_margins.left;
>+	s->tv_margins.top    = adj_mode->vdisplay * overscan / 200;
>+	s->tv_margins.bottom = s->tv_margins.top;
>+
> 	if (hdmi->tmds_char_rate == conn_state->hdmi.tmds_char_rate &&
> 	    s->output_bpc == conn_state->hdmi.output_bpc)
> 		return 0;
>@@ -603,6 +611,14 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
> 		return dev_err_probe(hdmi->dev, PTR_ERR(connector),
> 				     "Failed to init bridge connector\n");
> 
>+	ret = drm_mode_create_tv_properties_legacy(drm, 0, NULL);
>+	if (ret)
>+		return dev_err_probe(dev, ret,
>+				     "Failed to create TV connector properties\n");

      I suggest calling a similar API within rockchip_drm_bind, and then attaching this property in
the connector drivers that need to expose it. This approach avoids invoking the API multiple times in multiple drivers。

>+
>+	drm_object_attach_property(&connector->base,
>+				   drm->mode_config.tv_overscan_property, 0);
>+
> 	return 0;
> }
> 
>
>-- 
>2.52.0
>
>
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