Re: [PATCH 6/8] drm/bridge: dw-hdmi: move next_bridge lookup to attach time
From: Liu Ying <victor.liu@nxp.com>
Date: 2026-03-26 07:49:05
Also in:
dri-devel, imx, lkml
Hi Luca, On Fri, Mar 20, 2026 at 11:46:17AM +0100, Luca Ceresoli wrote:
quoted hunk ↗ jump to hunk
This driver looks up the next_bridge at probe time and stores it in hdmi->bridge.next_bridge, but only uses the stored value when attaching, and only in the DRM_BRIDGE_ATTACH_NO_CONNECTOR case. This will be problematic with an upcoming change, adding an hdmi-connector using a device tree overlay when not present. That change is in turn necessary to migrate the i.MX LCDIF driver to the bridge-connector. The problem is that, adding the hdmi-connector via an overlay, devlink considers hdmi-connector a consumer of the dw-hdmi device, generating a chicken-egg problem: * hdmi-connector probe won't be tried until dw-hdmi is probed (devlink) * dw-hdmi probe will defer until it finds the next_bridge (the hdmi-connector wrapper bridge) In preparation for those changes, move the next_bridge lookup from probe to attach, when it is actually used. This allows dw-hdmi to probe, so that the hdmi-connector can probe as well. Also avoid storing the pointer in hdmi->bridge.next_bridge: the value is computed when needed, thus a local variable is enough. Finally, this also allows to slightly improve the code by not doing any DT lookup in the !DRM_BRIDGE_ATTACH_NO_CONNECTOR case. Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com> --- drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 41 +++++++++---------------------- 1 file changed, 12 insertions(+), 29 deletions(-)diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index a668d66aeece..4ee865a1a6c8 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c@@ -2914,9 +2914,18 @@ static int dw_hdmi_bridge_attach(struct drm_bridge *bridge, if (WARN_ON((flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) && !hdmi->plat_data->output_port)) return -EINVAL; - if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) - return drm_bridge_attach(encoder, hdmi->bridge.next_bridge, - bridge, flags); + if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) { + struct device_node *remote __free(device_node) =
Include linux/cleanup.h as __free() is used.
+ of_graph_get_remote_node(hdmi->dev->of_node, + hdmi->plat_data->output_port, -1); + if (!remote) + return -EPROBE_DEFER;
Should return -ENODEV instead?
+ + struct drm_bridge *next_bridge __free(drm_bridge_put) = + of_drm_find_and_get_bridge(remote); + + return drm_bridge_attach(encoder, next_bridge, bridge, flags); + } return dw_hdmi_connector_create(hdmi); }
-- Regards, Liu Ying