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authorAlan Stern <stern@rowland.harvard.edu>2007-05-04 11:52:20 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-12 16:29:47 -0700
commit0458d5b4c9cc4ca0f62625d0144ddc4b4bc97a3c (patch)
tree8b1fcb4f063ef4aa6f2e3cd41a60d986a1e432d4 /drivers/usb/core/Kconfig
parentce7cd137fced114d49178b73d468b82096a107fb (diff)
downloadop-kernel-dev-0458d5b4c9cc4ca0f62625d0144ddc4b4bc97a3c.zip
op-kernel-dev-0458d5b4c9cc4ca0f62625d0144ddc4b4bc97a3c.tar.gz
USB: add USB-Persist facility
This patch (as886) adds the controversial USB-persist facility, allowing USB devices to persist across a power loss during system suspend. The facility is controlled by a new Kconfig option (with appropriate warnings about the potential dangers); when the option is off the behavior will remain the same as it is now. But when the option is on, people will be able to use suspend-to-disk and keep their USB filesystems intact -- something particularly valuable for small machines where the root filesystem is on a USB device! Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/Kconfig')
-rw-r--r--drivers/usb/core/Kconfig22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index 346fc03..5113ef4 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -86,6 +86,28 @@ config USB_SUSPEND
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, USB device data structures will remain
+ persistent across system suspend, even if the USB bus loses
+ power. (This includes software-suspend, 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
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