Merge branch 'master' of git.alsa-project.org:alsa-kernel into fix/hda

[pandora-kernel.git] / Documentation / usb / persist.txt

diff --git a/Documentation/usb/persist.txt b/Documentation/usb/persist.txt
index bea58db..074b159 100644 (file)
--- a/Documentation/usb/persist.txt
+++ b/Documentation/usb/persist.txt
@@ -81,8 +81,11 @@ re-enumeration shows that the device now attached to that port has the
 same descriptors as before, including the Vendor and Product IDs, then
 the kernel continues to use the same device structure.  In effect, the
 kernel treats the device as though it had merely been reset instead of
-unplugged.  The same thing happens if the host controller is in the
-expected state but a USB device was unplugged and then replugged.
+unplugged.
+
+The same thing happens if the host controller is in the expected state
+but a USB device was unplugged and then replugged, or if a USB device
+fails to carry out a normal resume.
 
 If no device is now attached to the port, or if the descriptors are
 different from what the kernel remembers, then the treatment is what
@@ -136,10 +139,10 @@ aren't guaranteed to be 100% accurate.
 
 If you replace one USB device with another of the same type (same
 manufacturer, same IDs, and so on) there's an excellent chance the
-kernel won't detect the change.  Serial numbers and other strings are
-not compared.  In many cases it wouldn't help if they were, because
-manufacturers frequently omit serial numbers entirely in their
-devices.
+kernel won't detect the change.  The serial number string and other
+descriptors are compared with the kernel's stored values, but this
+might not help since manufacturers frequently omit serial numbers
+entirely in their devices.
 
 Furthermore it's quite possible to leave a USB device exactly the same
 while changing its media.  If you replace the flash memory card in a