USB: remove CONFIG_USB_PERSIST setting
This patch (as1047) removes the USB_PERSIST Kconfig option, enabling
it permanently. It also prevents the power/persist attribute from
being created for hub devices; there's no point in having it since
USB-PERSIST is always turned on for hubs.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index a2b0aa4..c15621d 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -102,31 +102,6 @@
If you are unsure about this, say N here.
-config USB_PERSIST
- bool "USB device persistence during system suspend (DANGEROUS)"
- depends on USB && PM && EXPERIMENTAL
- default n
- help
-
- If you say Y here and enable the "power/persist" attribute
- for a USB device, the device's data structures will remain
- persistent across system suspend, even if the USB bus loses
- power. (This includes hibernation, also known as swsusp or
- suspend-to-disk.) The devices will reappear as if by magic
- when the system wakes up, with no need to unmount USB
- filesystems, rmmod host-controller drivers, or do anything
- else.
-
- WARNING: This option can be dangerous!
-
- If a USB device is replaced by another of the same type while
- the system is asleep, there's a good chance the kernel won't
- detect the change. Likewise if the media in a USB storage
- device is replaced. When this happens it's almost certain to
- cause data corruption and maybe even crash your system.
-
- If you are unsure, say N here.
-
config USB_OTG
bool
depends on USB && EXPERIMENTAL
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index df68e25..6dc5899 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -30,12 +30,6 @@
#include "hcd.h"
#include "hub.h"
-#ifdef CONFIG_USB_PERSIST
-#define USB_PERSIST 1
-#else
-#define USB_PERSIST 0
-#endif
-
/* if we are in debug mode, always announce new devices */
#ifdef DEBUG
#ifndef CONFIG_USB_ANNOUNCE_NEW_DEVICES
@@ -695,7 +689,7 @@
* turn off the various status changes to prevent
* khubd from disconnecting it later.
*/
- if (USB_PERSIST && udev->persist_enabled && status == 0 &&
+ if (udev->persist_enabled && status == 0 &&
!(portstatus & USB_PORT_STAT_ENABLE)) {
if (portchange & USB_PORT_STAT_C_ENABLE)
clear_port_feature(hub->hdev, port1,
@@ -1923,9 +1917,8 @@
* 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
+ * If @udev->reset_resume is set then this routine won't check that the
+ * port is still enabled. Furthermore, 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.
*
@@ -1937,8 +1930,8 @@
* 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
+ * This facility can be 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
@@ -1983,7 +1976,7 @@
status = hub_port_status(hub, port1, &portstatus, &portchange);
SuspendCleared:
- if (USB_PERSIST && udev->reset_resume)
+ if (udev->reset_resume)
want_flags = USB_PORT_STAT_POWER
| USB_PORT_STAT_CONNECTION;
else
@@ -2113,10 +2106,10 @@
*
* 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.
+ * has been reset. The routine marks @rhdev as having lost power.
+ * When the hub driver is resumed it will take notice and carry out
+ * power-session recovery for all the "USB-PERSIST"-enabled child devices;
+ * the others will be disconnected.
*/
void usb_root_hub_lost_power(struct usb_device *rhdev)
{
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index dfc5418..f384edf 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -97,4 +97,16 @@
if (udev->descriptor.bDeviceClass != USB_CLASS_HUB)
udev->autosuspend_disabled = 1;
#endif
+
+#ifdef CONFIG_PM
+ /* Hubs are automatically enabled for USB-PERSIST */
+ if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+ udev->persist_enabled = 1;
+#else
+ /* In the absense of PM, we can safely enable USB-PERSIST
+ * for all devices. It will affect things like hub resets
+ * and EMF-related port disables.
+ */
+ udev->persist_enabled = 1;
+#endif /* CONFIG_PM */
}
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index a37ccbd..5b20a60 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -180,11 +180,9 @@
static DEVICE_ATTR(urbnum, S_IRUGO, show_urbnum, NULL);
-#if defined(CONFIG_USB_PERSIST) || defined(CONFIG_USB_SUSPEND)
-static const char power_group[] = "power";
-#endif
+#ifdef CONFIG_PM
-#ifdef CONFIG_USB_PERSIST
+static const char power_group[] = "power";
static ssize_t
show_persist(struct device *dev, struct device_attribute *attr, char *buf)
@@ -222,12 +220,13 @@
if (is_usb_device(dev)) {
struct usb_device *udev = to_usb_device(dev);
- /* Hubs are automatically enabled for USB_PERSIST */
- if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
- udev->persist_enabled = 1;
- rc = sysfs_add_file_to_group(&dev->kobj,
- &dev_attr_persist.attr,
- power_group);
+ /* Hubs are automatically enabled for USB_PERSIST,
+ * no point in creating the attribute file.
+ */
+ if (udev->descriptor.bDeviceClass != USB_CLASS_HUB)
+ rc = sysfs_add_file_to_group(&dev->kobj,
+ &dev_attr_persist.attr,
+ power_group);
}
return rc;
}
@@ -238,13 +237,12 @@
&dev_attr_persist.attr,
power_group);
}
-
#else
#define add_persist_attributes(dev) 0
#define remove_persist_attributes(dev) do {} while (0)
-#endif /* CONFIG_USB_PERSIST */
+#endif /* CONFIG_PM */
#ifdef CONFIG_USB_SUSPEND
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 8d513a1..fea9e47 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -28,7 +28,7 @@
/*-------------------------------------------------------------------------*/
-#ifdef CONFIG_USB_PERSIST
+#ifdef CONFIG_PM
static int ehci_hub_control(
struct usb_hcd *hcd,
@@ -104,15 +104,6 @@
ehci->owned_ports = 0;
}
-#else /* CONFIG_USB_PERSIST */
-
-static inline void ehci_handover_companion_ports(struct ehci_hcd *ehci)
-{ }
-
-#endif
-
-#ifdef CONFIG_PM
-
static int ehci_bus_suspend (struct usb_hcd *hcd)
{
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
