** Summary changed:

- Powertop suggest to add usbcore.autosuspend=1 to grub's kernel line, doesn't 
work
+ Powertop make wrong suggest to add usbcore.autosuspend=1

** Description changed:

  Binary package hint: powertop
  
- When running powertop, it suggest adding the usbcore.autosuspend=1 to
- grub's kernel line to turn on usb autosuspend powermanagement.
- Unfortunately, when booting you get this error message:
+ Powertop make wrong suggestion to enable "usbcore autosuspend=1" if it find 
device set to autosuspedn=0.
+ According to documentation of "Power Management for USB" (, Alan Stern 
<[EMAIL PROTECTED]>, October 5, 2007. )  
+ kernel, up version 2.6.22, use 0 for "autosuspend as soon as the device 
becomes idle" but -1 means never to autosuspend.
+ ......
+ The user interface for dynamic PM
+ .....
+  power/autosuspend
  
- unknown boot option : usbcore.autosuspend=1 ignoring
+                 This file contains an integer value, which is the
+                 number of seconds the device should remain idle before
+                 the kernel will autosuspend it (the idle-delay time).
+                 The default is 2.  0 means to autosuspend as soon as
+                 the device becomes idle, and -1 means never to
+                 autosuspend.  You can write a number to the file to
+                 change the autosuspend idle-delay time.
  
- I have read somewhere that this autosuspend should be added to
- /etc/sysfs.conf after installing sysfsutils
+ Writing "-1" to power/autosuspend and writing "on" to power/level do
+ essentially the same thing -- they both prevent the device from being
+ autosuspended.  Yes, this is a redundancy in the API.
  
- module/usbcore/parameters/autosuspend = 1
+ (In 2.6.21 writing "0" to power/autosuspend would prevent the device
+ from being autosuspended; the behavior was changed in 2.6.22.  The
+ power/autosuspend attribute did not exist prior to 2.6.21, and the
+ power/level attribute did not exist prior to 2.6.22.)
  
- but i'm not sure that works.
+ 
+ Regards,
+ Alex

-- 
Powertop make wrong suggest to add usbcore.autosuspend=1
https://bugs.launchpad.net/bugs/136549
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