Commit 9262c19d14c4 "usb: disable port power control if not supported in wHubCharacteristics" gated enabling runtime pm for usb_port devices on whether the parent hub supports power control, which causes a regression. The port must still be allowed to carry out runtime pm callbacks and receive a -EAGAIN or -EBUSY result. Otherwise the usb_port device will transition to the pm error state and trigger the same for the child usb_device.
Prior to the offending commit usb_hub_create_port_device() arranged for runtime pm to be disabled is dev_pm_qos_expose_flags() failed. Instead, force the default state of PM_QOS_FLAG_NO_POWER_OFF flag to be set prior to enabling runtime pm. If that policy can not be set then fail registration. Report: http://marc.info/?l=linux-usb&m=140290586301336&w=2 Fixes: 9262c19d14c4 ("usb: disable port power control if not supported in wHubCharacteristics") Reported-by: Bjørn Mork <bj...@mork.no> Reported-by: Alan Stern <st...@rowland.harvard.edu> Signed-off-by: Dan Williams <dan.j.willi...@intel.com> --- drivers/usb/core/hub.c | 6 ++++ drivers/usb/core/hub.h | 2 + drivers/usb/core/port.c | 65 +++++++++++++++++++++++++++++++++-------------- 3 files changed, 54 insertions(+), 19 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 6ac87cbf3af7..e476e767c8de 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1589,6 +1589,12 @@ static int hub_configure(struct usb_hub *hub, } } hdev->maxchild = i; + for (i = 0; i < hdev->maxchild; i++) { + struct usb_port *port_dev = hub->ports[i]; + + pm_runtime_put(&port_dev->dev); + } + mutex_unlock(&usb_port_peer_mutex); if (ret < 0) goto fail; diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 0a7cdc0ef0a9..326308e53961 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -84,6 +84,7 @@ struct usb_hub { * @dev: generic device interface * @port_owner: port's owner * @peer: related usb2 and usb3 ports (share the same connector) + * @req: default pm qos request for hubs without port power control * @connect_type: port's connect type * @location: opaque representation of platform connector location * @status_lock: synchronize port_event() vs usb_port_{suspend|resume} @@ -95,6 +96,7 @@ struct usb_port { struct device dev; struct usb_dev_state *port_owner; struct usb_port *peer; + struct dev_pm_qos_request *req; enum usb_port_connect_type connect_type; usb_port_location_t location; struct mutex status_lock; diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index 9347ade7d5fe..fe1b6d0967e3 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -68,6 +68,7 @@ static void usb_port_device_release(struct device *dev) { struct usb_port *port_dev = to_usb_port(dev); + kfree(port_dev->req); kfree(port_dev); } @@ -400,9 +401,13 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) int retval; port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL); - if (!port_dev) { - retval = -ENOMEM; - goto exit; + if (!port_dev) + return -ENOMEM; + + port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL); + if (!port_dev->req) { + kfree(port_dev); + return -ENOMEM; } hub->ports[port1 - 1] = port_dev; @@ -418,31 +423,53 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) port1); mutex_init(&port_dev->status_lock); retval = device_register(&port_dev->dev); - if (retval) - goto error_register; + if (retval) { + put_device(&port_dev->dev); + return retval; + } + + /* Set default policy of port-poweroff disabled. */ + retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req, + DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF); + if (retval < 0) { + device_unregister(&port_dev->dev); + return retval; + } find_and_link_peer(hub, port1); + /* + * Enable runtime pm and hold a refernce that hub_configure() + * will drop once the PM_QOS_NO_POWER_OFF flag state has been set + * and the hub has been fully registered (hdev->maxchild set). + */ pm_runtime_set_active(&port_dev->dev); + pm_runtime_get_noresume(&port_dev->dev); + pm_runtime_enable(&port_dev->dev); + device_enable_async_suspend(&port_dev->dev); /* - * Do not enable port runtime pm if the hub does not support - * power switching. Also, userspace must have final say of - * whether a port is permitted to power-off. Do not enable - * runtime pm if we fail to expose pm_qos_no_power_off. + * Keep hidden the ability to enable port-poweroff if the hub + * does not support power switching. */ - if (hub_is_port_power_switchable(hub) - && dev_pm_qos_expose_flags(&port_dev->dev, - PM_QOS_FLAG_NO_POWER_OFF) == 0) - pm_runtime_enable(&port_dev->dev); + if (!hub_is_port_power_switchable(hub)) + return 0; - device_enable_async_suspend(&port_dev->dev); - return 0; + /* Attempt to let userspace take over the policy. */ + retval = dev_pm_qos_expose_flags(&port_dev->dev, + PM_QOS_FLAG_NO_POWER_OFF); + if (retval < 0) { + dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n"); + return 0; + } -error_register: - put_device(&port_dev->dev); -exit: - return retval; + /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */ + retval = dev_pm_qos_remove_request(port_dev->req); + if (retval >= 0) { + kfree(port_dev->req); + port_dev->req = NULL; + } + return 0; } void usb_hub_remove_port_device(struct usb_hub *hub, int port1) -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
