6.9-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Baryshkov dmitry.baryshkov@linaro.org
[ Upstream commit 718b36a7b49acbba36546371db2d235271ceb06c ]
If a probe function returns -EPROBE_DEFER after creating another device there is a change of ending up in a probe deferral loop, (see commit fbc35b45f9f6 ("Add documentation on meaning of -EPROBE_DEFER"). In case of the qcom-pmic-typec driver the tcpm_register_port() function looks up external resources (USB role switch and inherently via called typec_register_port() USB-C muxes, switches and retimers).
In order to prevent such probe-defer loops caused by qcom-pmic-typec driver, use the API added by Johan Hovold and move HPD bridge registration to the end of the probe function.
The devm_drm_dp_hpd_bridge_add() is called at the end of the probe function after all TCPM start functions. This is done as a way to overcome a different problem, the DRM subsystem can not properly cope with the DRM bridges being destroyed once the bridge is attached. Having this function call at the end of the probe function prevents possible DRM bridge device creation followed by destruction in case one of the TCPM start functions returns an error.
Reported-by: Caleb Connolly caleb.connolly@linaro.org Acked-by: Bryan O'Donoghue bryan.odonoghue@linaro.org Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Johan Hovold johan+linaro@kernel.org Link: https://lore.kernel.org/r/20240424-qc-pmic-typec-hpd-split-v4-1-f7e10d147443... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c index d3958c061a972..501eddb294e43 100644 --- a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c +++ b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c @@ -41,7 +41,7 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev) struct device_node *np = dev->of_node; const struct pmic_typec_resources *res; struct regmap *regmap; - struct device *bridge_dev; + struct auxiliary_device *bridge_dev; u32 base; int ret;
@@ -92,7 +92,7 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev) if (!tcpm->tcpc.fwnode) return -EINVAL;
- bridge_dev = drm_dp_hpd_bridge_register(tcpm->dev, to_of_node(tcpm->tcpc.fwnode)); + bridge_dev = devm_drm_dp_hpd_bridge_alloc(tcpm->dev, to_of_node(tcpm->tcpc.fwnode)); if (IS_ERR(bridge_dev)) return PTR_ERR(bridge_dev);
@@ -110,8 +110,14 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev) if (ret) goto port_stop;
+ ret = devm_drm_dp_hpd_bridge_add(tcpm->dev, bridge_dev); + if (ret) + goto pdphy_stop; + return 0;
+pdphy_stop: + tcpm->pdphy_stop(tcpm); port_stop: tcpm->port_stop(tcpm); port_unregister: