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-rw-r--r--drivers/usb/core/generic.c2
-rw-r--r--drivers/usb/core/hub.c184
-rw-r--r--drivers/usb/core/usb.h1
3 files changed, 93 insertions, 94 deletions
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
index 4cbe7b33951..b2fc2b11525 100644
--- a/drivers/usb/core/generic.c
+++ b/drivers/usb/core/generic.c
@@ -219,8 +219,6 @@ static int generic_resume(struct usb_device *udev)
*/
if (!udev->parent)
rc = hcd_bus_resume(udev);
- else if (udev->reset_resume)
- rc = usb_reset_suspended_device(udev);
else
rc = usb_port_resume(udev);
return rc;
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 0b8ed414d5c..c4cdb69a6e9 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -31,6 +31,12 @@
#include "hcd.h"
#include "hub.h"
+#ifdef CONFIG_USB_PERSIST
+#define USB_PERSIST 1
+#else
+#define USB_PERSIST 0
+#endif
+
struct usb_hub {
struct device *intfdev; /* the "interface" device */
struct usb_device *hdev;
@@ -1080,72 +1086,6 @@ void usb_set_device_state(struct usb_device *udev,
spin_unlock_irqrestore(&device_state_lock, flags);
}
-
-#ifdef CONFIG_PM
-
-/**
- * usb_reset_suspended_device - reset a suspended device instead of resuming it
- * @udev: device to be reset instead of resumed
- *
- * If a host controller doesn't maintain VBUS suspend current during a
- * system sleep or is reset when the system wakes up, all the USB
- * power sessions below it will be broken. This is especially troublesome
- * for mass-storage devices containing mounted filesystems, since the
- * device will appear to have disconnected and all the memory mappings
- * to it will be lost.
- *
- * As an alternative, this routine attempts to recover power sessions for
- * devices that are still present by resetting them instead of resuming
- * them. If all goes well, the devices will appear to persist across the
- * the interruption of the power sessions.
- *
- * This facility is inherently dangerous. Although usb_reset_device()
- * makes every effort to insure that the same device is present after the
- * reset as before, it cannot provide a 100% guarantee. Furthermore it's
- * quite possible for a device to remain unaltered but its media to be
- * changed. If the user replaces a flash memory card while the system is
- * asleep, he will have only himself to blame when the filesystem on the
- * new card is corrupted and the system crashes.
- */
-int usb_reset_suspended_device(struct usb_device *udev)
-{
- int rc = 0;
-
- dev_dbg(&udev->dev, "usb %sresume\n", "reset-");
-
- /* After we're done the device won't be suspended any more.
- * In addition, the reset won't work if udev->state is SUSPENDED.
- */
- usb_set_device_state(udev, udev->actconfig
- ? USB_STATE_CONFIGURED
- : USB_STATE_ADDRESS);
-
- /* Root hubs don't need to be (and can't be) reset */
- if (udev->parent)
- rc = usb_reset_device(udev);
- return rc;
-}
-
-/**
- * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
- * @rhdev: struct usb_device for the root hub
- *
- * The USB host controller driver calls this function when its root hub
- * is resumed and Vbus power has been interrupted or the controller
- * has been reset. The routine marks @rhdev as having lost power. When
- * the hub driver is resumed it will take notice; if CONFIG_USB_PERSIST
- * is enabled then it will carry out power-session recovery, otherwise
- * it will disconnect all the child devices.
- */
-void usb_root_hub_lost_power(struct usb_device *rhdev)
-{
- dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
- rhdev->reset_resume = 1;
-}
-EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
-
-#endif /* CONFIG_PM */
-
static void choose_address(struct usb_device *udev)
{
int devnum;
@@ -1672,18 +1612,22 @@ int usb_port_suspend(struct usb_device *udev)
/*
* If the USB "suspend" state is in use (rather than "global suspend"),
* many devices will be individually taken out of suspend state using
- * special" resume" signaling. These routines kick in shortly after
+ * special "resume" signaling. This routine kicks in shortly after
* hardware resume signaling is finished, either because of selective
* resume (by host) or remote wakeup (by device) ... now see what changed
* in the tree that's rooted at this device.
+ *
+ * If @udev->reset_resume is set then the device is reset before the
+ * status check is done.
*/
static int finish_port_resume(struct usb_device *udev)
{
- int status;
+ int status = 0;
u16 devstatus;
/* caller owns the udev device lock */
- dev_dbg(&udev->dev, "finish resume\n");
+ dev_dbg(&udev->dev, "finish %sresume\n",
+ udev->reset_resume ? "reset-" : "");
/* usb ch9 identifies four variants of SUSPENDED, based on what
* state the device resumes to. Linux currently won't see the
@@ -1694,13 +1638,23 @@ static int finish_port_resume(struct usb_device *udev)
? USB_STATE_CONFIGURED
: USB_STATE_ADDRESS);
+ /* 10.5.4.5 says not to reset a suspended port if the attached
+ * device is enabled for remote wakeup. Hence the reset
+ * operation is carried out here, after the port has been
+ * resumed.
+ */
+ if (udev->reset_resume)
+ status = usb_reset_device(udev);
+
/* 10.5.4.5 says be sure devices in the tree are still there.
* For now let's assume the device didn't go crazy on resume,
* and device drivers will know about any resume quirks.
*/
- status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
- if (status >= 0)
- status = (status == 2 ? 0 : -ENODEV);
+ if (status == 0) {
+ status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
+ if (status >= 0)
+ status = (status == 2 ? 0 : -ENODEV);
+ }
if (status) {
dev_dbg(&udev->dev, "gone after usb resume? status %d\n",
@@ -1735,6 +1689,28 @@ static int finish_port_resume(struct usb_device *udev)
* the host and the device is the same as it was when the device
* suspended.
*
+ * If CONFIG_USB_PERSIST and @udev->reset_resume are both set then this
+ * routine won't check that the port is still enabled. Furthermore,
+ * if @udev->reset_resume is set then finish_port_resume() above will
+ * reset @udev. The end result is that a broken power session can be
+ * recovered and @udev will appear to persist across a loss of VBUS power.
+ *
+ * For example, if a host controller doesn't maintain VBUS suspend current
+ * during a system sleep or is reset when the system wakes up, all the USB
+ * power sessions below it will be broken. This is especially troublesome
+ * for mass-storage devices containing mounted filesystems, since the
+ * device will appear to have disconnected and all the memory mappings
+ * to it will be lost. Using the USB_PERSIST facility, the device can be
+ * made to appear as if it had not disconnected.
+ *
+ * This facility is inherently dangerous. Although usb_reset_device()
+ * makes every effort to insure that the same device is present after the
+ * reset as before, it cannot provide a 100% guarantee. Furthermore it's
+ * quite possible for a device to remain unaltered but its media to be
+ * changed. If the user replaces a flash memory card while the system is
+ * asleep, he will have only himself to blame when the filesystem on the
+ * new card is corrupted and the system crashes.
+ *
* Returns 0 on success, else negative errno.
*/
int usb_port_resume(struct usb_device *udev)
@@ -1743,6 +1719,7 @@ int usb_port_resume(struct usb_device *udev)
int port1 = udev->portnum;
int status;
u16 portchange, portstatus;
+ unsigned mask_flags, want_flags;
/* Skip the initial Clear-Suspend step for a remote wakeup */
status = hub_port_status(hub, port1, &portstatus, &portchange);
@@ -1765,20 +1742,23 @@ int usb_port_resume(struct usb_device *udev)
udev->auto_pm ? "auto-" : "");
msleep(25);
-#define LIVE_FLAGS ( USB_PORT_STAT_POWER \
- | USB_PORT_STAT_ENABLE \
- | USB_PORT_STAT_CONNECTION)
-
/* Virtual root hubs can trigger on GET_PORT_STATUS to
* stop resume signaling. Then finish the resume
* sequence.
*/
status = hub_port_status(hub, port1, &portstatus, &portchange);
-SuspendCleared:
- if (status < 0
- || (portstatus & LIVE_FLAGS) != LIVE_FLAGS
- || (portstatus & USB_PORT_STAT_SUSPEND) != 0
- ) {
+
+ SuspendCleared:
+ if (USB_PERSIST && udev->reset_resume)
+ want_flags = USB_PORT_STAT_POWER
+ | USB_PORT_STAT_CONNECTION;
+ else
+ want_flags = USB_PORT_STAT_POWER
+ | USB_PORT_STAT_CONNECTION
+ | USB_PORT_STAT_ENABLE;
+ mask_flags = want_flags | USB_PORT_STAT_SUSPEND;
+
+ if (status < 0 || (portstatus & mask_flags) != want_flags) {
dev_dbg(hub->intfdev,
"port %d status %04x.%04x after resume, %d\n",
port1, portchange, portstatus, status);
@@ -1790,18 +1770,19 @@ SuspendCleared:
USB_PORT_FEAT_C_SUSPEND);
/* TRSMRCY = 10 msec */
msleep(10);
- status = finish_port_resume(udev);
}
}
- if (status < 0) {
- dev_dbg(&udev->dev, "can't resume, status %d\n", status);
- hub_port_logical_disconnect(hub, port1);
- }
clear_bit(port1, hub->busy_bits);
if (!hub->hdev->parent && !hub->busy_bits[0])
usb_enable_root_hub_irq(hub->hdev->bus);
+ if (status == 0)
+ status = finish_port_resume(udev);
+ if (status < 0) {
+ dev_dbg(&udev->dev, "can't resume, status %d\n", status);
+ hub_port_logical_disconnect(hub, port1);
+ }
return status;
}
@@ -1830,7 +1811,14 @@ int usb_port_suspend(struct usb_device *udev)
int usb_port_resume(struct usb_device *udev)
{
- return 0;
+ int status = 0;
+
+ /* However we may need to do a reset-resume */
+ if (udev->reset_resume) {
+ dev_dbg(&udev->dev, "reset-resume\n");
+ status = usb_reset_device(udev);
+ }
+ return status;
}
static inline int remote_wakeup(struct usb_device *udev)
@@ -1886,8 +1874,6 @@ static int hub_resume(struct usb_interface *intf)
#ifdef CONFIG_USB_PERSIST
-#define USB_PERSIST 1
-
/* For "persistent-device" resets we must mark the child devices for reset
* and turn off a possible connect-change status (so khubd won't disconnect
* them later).
@@ -1910,8 +1896,6 @@ static void mark_children_for_reset_resume(struct usb_hub *hub)
#else
-#define USB_PERSIST 0
-
static inline void mark_children_for_reset_resume(struct usb_hub *hub)
{ }
@@ -1936,6 +1920,24 @@ static int hub_reset_resume(struct usb_interface *intf)
return 0;
}
+/**
+ * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
+ * @rhdev: struct usb_device for the root hub
+ *
+ * The USB host controller driver calls this function when its root hub
+ * is resumed and Vbus power has been interrupted or the controller
+ * has been reset. The routine marks @rhdev as having lost power. When
+ * the hub driver is resumed it will take notice; if CONFIG_USB_PERSIST
+ * is enabled then it will carry out power-session recovery, otherwise
+ * it will disconnect all the child devices.
+ */
+void usb_root_hub_lost_power(struct usb_device *rhdev)
+{
+ dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
+ rhdev->reset_resume = 1;
+}
+EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
+
#else /* CONFIG_PM */
static inline int remote_wakeup(struct usb_device *udev)
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index a547499c45f..ad5fa0338f4 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -36,7 +36,6 @@ extern void usb_host_cleanup(void);
extern void usb_autosuspend_work(struct work_struct *work);
extern int usb_port_suspend(struct usb_device *dev);
extern int usb_port_resume(struct usb_device *dev);
-extern int usb_reset_suspended_device(struct usb_device *udev);
extern int usb_external_suspend_device(struct usb_device *udev,
pm_message_t msg);
extern int usb_external_resume_device(struct usb_device *udev);