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5c79a1e303
In general we do not want khubd to act on port status changes that are
the result of in progress resets or USB runtime PM operations.
Specifically port power control testing has been able to trigger an
unintended disconnect in hub_port_connect_change(), paraphrasing:
if ((portstatus & USB_PORT_STAT_CONNECTION) && udev &&
udev->state != USB_STATE_NOTATTACHED) {
if (portstatus & USB_PORT_STAT_ENABLE) {
/* Nothing to do */
} else if (udev->state == USB_STATE_SUSPENDED &&
udev->persist_enabled) {
...
} else {
/* Don't resuscitate */;
}
}
...by falling to the "Don't resuscitate" path or missing
USB_PORT_STAT_CONNECTION because usb_port_resume() was in the middle of
modifying the port status.
So, we want a new lock to hold off khubd for a given port while the
child device is being suspended, resumed, or reset. The lock ordering
rules are now usb_lock_device() => usb_lock_port(). This is mandated by
the device core which may hold the device_lock on the usb_device before
invoking usb_port_{suspend|resume} which in turn take the status_lock on
the usb_port. We attempt to hold the status_lock for the duration of a
port_event() run, and drop/re-acquire it when needing to take the
device_lock. The lock is also dropped/re-acquired during
hub_port_reconnect().
This patch also deletes hub->busy_bits as all use cases are now covered
by port PM runtime synchronization or the port->status_lock and it
pushes down usb_device_lock() into usb_remote_wakeup().
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
154 lines
4.6 KiB
C
154 lines
4.6 KiB
C
/*
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* usb hub driver head file
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*
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* Copyright (C) 1999 Linus Torvalds
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* Copyright (C) 1999 Johannes Erdfelt
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* Copyright (C) 1999 Gregory P. Smith
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* Copyright (C) 2001 Brad Hards (bhards@bigpond.net.au)
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* Copyright (C) 2012 Intel Corp (tianyu.lan@intel.com)
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*
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* move struct usb_hub to this file.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <linux/usb.h>
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#include <linux/usb/ch11.h>
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#include <linux/usb/hcd.h>
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#include "usb.h"
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struct usb_hub {
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struct device *intfdev; /* the "interface" device */
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struct usb_device *hdev;
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struct kref kref;
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struct urb *urb; /* for interrupt polling pipe */
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/* buffer for urb ... with extra space in case of babble */
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u8 (*buffer)[8];
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union {
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struct usb_hub_status hub;
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struct usb_port_status port;
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} *status; /* buffer for status reports */
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struct mutex status_mutex; /* for the status buffer */
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int error; /* last reported error */
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int nerrors; /* track consecutive errors */
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struct list_head event_list; /* hubs w/data or errs ready */
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unsigned long event_bits[1]; /* status change bitmask */
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unsigned long change_bits[1]; /* ports with logical connect
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status change */
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unsigned long removed_bits[1]; /* ports with a "removed"
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device present */
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unsigned long wakeup_bits[1]; /* ports that have signaled
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remote wakeup */
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unsigned long power_bits[1]; /* ports that are powered */
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unsigned long child_usage_bits[1]; /* ports powered on for
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children */
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#if USB_MAXCHILDREN > 31 /* 8*sizeof(unsigned long) - 1 */
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#error event_bits[] is too short!
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#endif
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struct usb_hub_descriptor *descriptor; /* class descriptor */
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struct usb_tt tt; /* Transaction Translator */
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unsigned mA_per_port; /* current for each child */
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#ifdef CONFIG_PM
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unsigned wakeup_enabled_descendants;
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#endif
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unsigned limited_power:1;
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unsigned quiescing:1;
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unsigned disconnected:1;
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unsigned in_reset:1;
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unsigned quirk_check_port_auto_suspend:1;
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unsigned has_indicators:1;
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u8 indicator[USB_MAXCHILDREN];
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struct delayed_work leds;
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struct delayed_work init_work;
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struct usb_port **ports;
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};
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/**
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* struct usb port - kernel's representation of a usb port
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* @child: usb device attached to the port
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* @dev: generic device interface
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* @port_owner: port's owner
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* @peer: related usb2 and usb3 ports (share the same connector)
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* @connect_type: port's connect type
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* @location: opaque representation of platform connector location
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* @status_lock: synchronize port_event() vs usb_port_{suspend|resume}
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* @portnum: port index num based one
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* @is_superspeed cache super-speed status
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*/
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struct usb_port {
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struct usb_device *child;
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struct device dev;
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struct usb_dev_state *port_owner;
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struct usb_port *peer;
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enum usb_port_connect_type connect_type;
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usb_port_location_t location;
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struct mutex status_lock;
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u8 portnum;
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unsigned int is_superspeed:1;
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};
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#define to_usb_port(_dev) \
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container_of(_dev, struct usb_port, dev)
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extern int usb_hub_create_port_device(struct usb_hub *hub,
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int port1);
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extern void usb_hub_remove_port_device(struct usb_hub *hub,
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int port1);
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extern int usb_hub_set_port_power(struct usb_device *hdev, struct usb_hub *hub,
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int port1, bool set);
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extern struct usb_hub *usb_hub_to_struct_hub(struct usb_device *hdev);
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extern int hub_port_debounce(struct usb_hub *hub, int port1,
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bool must_be_connected);
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extern int usb_clear_port_feature(struct usb_device *hdev,
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int port1, int feature);
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static inline bool hub_is_port_power_switchable(struct usb_hub *hub)
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{
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__le16 hcs;
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if (!hub)
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return false;
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hcs = hub->descriptor->wHubCharacteristics;
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return (le16_to_cpu(hcs) & HUB_CHAR_LPSM) < HUB_CHAR_NO_LPSM;
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}
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static inline int hub_is_superspeed(struct usb_device *hdev)
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{
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return hdev->descriptor.bDeviceProtocol == USB_HUB_PR_SS;
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}
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static inline unsigned hub_power_on_good_delay(struct usb_hub *hub)
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{
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unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2;
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/* Wait at least 100 msec for power to become stable */
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return max(delay, 100U);
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}
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static inline int hub_port_debounce_be_connected(struct usb_hub *hub,
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int port1)
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{
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return hub_port_debounce(hub, port1, true);
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}
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static inline int hub_port_debounce_be_stable(struct usb_hub *hub,
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int port1)
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{
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return hub_port_debounce(hub, port1, false);
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}
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