[bug report] drm/rockchip: dw_hdmi: Propagate bus format to display driver

From: Dan Carpenter <error27@gmail.com>
To: Jonas Karlman <jonas@kwiboo.se>
Cc: linux-rockchip@lists.infradead.org
Subject: [bug report] drm/rockchip: dw_hdmi: Propagate bus format to display driver
Date: Thu, 13 Aug 2026 10:08:39 +0300	[thread overview]
Message-ID: <an1td9BdKRo2JUDy@stanley.mountain> (raw)

Hello Jonas Karlman,

Commit dc70272cc184 ("drm/rockchip: dw_hdmi: Propagate bus format to
display driver") from May 18, 2026 (linux-next), leads to the
following Smatch static checker warning:

	drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c:292 dw_hdmi_rockchip_get_bus_format()
	error: 'bridge_state' dereferencing possible ERR_PTR()

drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
    278 static u32 dw_hdmi_rockchip_get_bus_format(struct drm_encoder *encoder,
    279                                            struct drm_connector_state *conn_state)
    280 {
    281         struct drm_bridge *bridge __free(drm_bridge_put) = NULL;
    282         struct drm_bridge_state *bridge_state;
    283 
    284         bridge = drm_bridge_chain_get_first_bridge(encoder);
    285         if (!bridge)
    286                 return 0;
    287 
    288         bridge_state = drm_atomic_get_bridge_state(conn_state->state, bridge);
    289         if (!bridge_state)

This should be if (IS_ERR(bridge_state)).

    290                 return 0;
    291 
--> 292         if (bridge_state->input_bus_cfg.format != MEDIA_BUS_FMT_FIXED)
    293                 return bridge_state->input_bus_cfg.format;
    294 
    295         return bridge_state->output_bus_cfg.format;
    296 }

This email is a free service from the Smatch-CI project [smatch.sf.net].

regards,
dan carpenter

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