Re: [PATCH v11 01/21] drm/bridge: synopsys: dw-dp: Register DP AUX on bridge attach

Sebastian Reichel <[email protected]> Mon, 17 Aug 2026 18:19:37 +0200
Newsgroups	org.infradead.lists.linux-rockchip,org.freedesktop.lists.dri-devel,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID	<aoM0KMBoIpIQ5vnw@venus>
Hello Andy,

On Sun, Aug 16, 2026 at 08:37:21PM +0800, Andy Yan wrote:
> Hello Sebastian，
> 
> At 2026-08-07 01:02:07, "Sebastian Reichel" <[email protected]> wrote:
> >Unregister the DP AUX device at the right spot as documented in the
> >drm_dp_aux_register() function description. This helps that it is
> >only accessed when the DRM device is ready and the bridge is powered
> >and initialized (further fixes are required for that).
> >
> >Fixes: 86eecc3a9c2e ("drm/bridge: synopsys: Add DW DPTX Controller support library")
> >Reported-by: Sashiko <[email protected]>
> >Signed-off-by: Sebastian Reichel <[email protected]>
> >---
> > drivers/gpu/drm/bridge/synopsys/dw-dp.c | 55 +++++++++++++++++++++------------
> > 1 file changed, 35 insertions(+), 20 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >index 8b8529e1723c..60feb3d1e14b 100644
> >--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >@@ -1813,7 +1813,36 @@ static struct drm_bridge_state *dw_dp_bridge_atomic_duplicate_state(struct drm_b
> > 	return &state->base;
> > }
> > 
> >+static int dw_dp_bridge_attach(struct drm_bridge *bridge,
> >+			       struct drm_encoder *encoder,
> >+			       enum drm_bridge_attach_flags flags)
> >+{
> >+	struct dw_dp *dp = bridge_to_dp(bridge);
> >+	struct device *dev = dp->dev;
> >+	int ret;
> >+
> >+	dp->aux.dev = dev;
> >+	dp->aux.drm_dev = encoder->dev;
> >+	dp->aux.name = dev_name(dev);
> >+	dp->aux.transfer = dw_dp_aux_transfer;
> >+
> >+	ret = drm_dp_aux_register(&dp->aux);
> >+	if (ret)
> >+		dev_err(dev, "Aux register failed: %d\n", ret);
> >+
> >+	return ret;
> >+}
> >+
> >+static void dw_dp_bridge_detach(struct drm_bridge *bridge)
> >+{
> >+	struct dw_dp *dp = bridge_to_dp(bridge);
> >+
> >+	drm_dp_aux_unregister(&dp->aux);
> >+}
> >+
> > static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
> >+	.attach = dw_dp_bridge_attach,
> >+	.detach = dw_dp_bridge_detach,
> > 	.atomic_duplicate_state = dw_dp_bridge_atomic_duplicate_state,
> > 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> > 	.atomic_create_state = drm_atomic_helper_bridge_create_state,
> >@@ -2043,20 +2072,10 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
> > 	if (ret)
> > 		return ERR_PTR(ret);
> > 
> >-	dp->aux.dev = dev;
> >-	dp->aux.drm_dev = encoder->dev;
> >-	dp->aux.name = dev_name(dev);
> >-	dp->aux.transfer = dw_dp_aux_transfer;
> >-	ret = drm_dp_aux_register(&dp->aux);
> >-	if (ret) {
> >-		dev_err_probe(dev, ret, "Aux register failed\n");
> >-		return ERR_PTR(ret);
> >-	}
> >-
> > 	ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > 	if (ret) {
> > 		dev_err_probe(dev, ret, "Failed to attach bridge\n");
> >-		goto unregister_aux;
> >+		return ERR_PTR(ret);
> > 	}
> > 
> > 	dw_dp_init_hw(dp);
> >@@ -2064,37 +2083,33 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
> > 	ret = phy_init(dp->phy);
> > 	if (ret) {
> > 		dev_err_probe(dev, ret, "phy init failed\n");
> >-		goto unregister_aux;
> >+		return ERR_PTR(ret);
> > 	}
> > 
> > 	ret = devm_add_action_or_reset(dev, dw_dp_phy_exit, dp);
> > 	if (ret)
> >-		goto unregister_aux;
> >+		return ERR_PTR(ret);
> > 
> > 	dp->irq = platform_get_irq(pdev, 0);
> > 	if (dp->irq < 0) {
> > 		ret = dp->irq;
> >-		goto unregister_aux;
> >+		return ERR_PTR(ret);
> > 	}
> > 
> > 	ret = devm_request_threaded_irq(dev, dp->irq, NULL, dw_dp_irq,
> > 					IRQF_ONESHOT, dev_name(dev), dp);
> > 	if (ret) {
> > 		dev_err_probe(dev, ret, "failed to request irq\n");
> 
> 
>   After this patch[0]  is applied, there will be a conflict here.
> 
>  [0]https://lore.kernel.org/all/[email protected]/#t

This got applied after I send this. I do rebase to latest
drm-misc-next on every submission, so it will be fixed with the next
version.

Greetings,

-- Sebastian

> 
> 
> >-		goto unregister_aux;
> >+		return ERR_PTR(ret);
> > 	}
> 
> 
> 
> > 
> > 	return dp;
> >-
> >-unregister_aux:
> >-	drm_dp_aux_unregister(&dp->aux);
> >-	return ERR_PTR(ret);
> > }
> > EXPORT_SYMBOL_GPL(dw_dp_bind);
> > 
> > void dw_dp_unbind(struct dw_dp *dp)
> > {
> >-	drm_dp_aux_unregister(&dp->aux);
> >+	/* nothing to do */
> > }
> > EXPORT_SYMBOL_GPL(dw_dp_unbind);
> > 
> >
> >-- 
> >2.53.0
> >

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