USB3.0 LPM: Achieving A Reduced-power Bus State

[chsdkj]

I'm looking for a way to cause an external USB3.0 device, such as an
HDD, to enter and exit the reduced-power USB mode (e.g., leave/enter the
U0 power state) for bus-testing purposes.

Presumably, all that is needed to be done is to set the Power Options on
the Windows Control Panel to cause hard disks in the system to turn off
after being idle for e.g. 1 minute.  However, using a Win-7/64-bit
laptop with a USB3.0 controller card and an external HDD having a USB3.0
interface, monitoring the USB3.0 bus showed that the usual background
bus activity never ceased (e.g., after 1 minute).  Note the
possibly-important detail that there is a USB3.0 hub present between the
host controller card and the HDD, with the analyzer connected between
the hub and the HDD.

I have heard that there is or might be a USB3.0 LPM software utility
that (presumably) could be used to command (or request) the USB3.0
controller to put the link(s) out to the HDD into a non-U0 state, but I
have not seen references to same on the Internet.

Any help would be appreciated.  What would be
sufficient, if no such handy utility application exists, is information
regarding what host system (brand/manufacturer) running what version of
Windows, and what USB3.0 device (brand/manufacturer), are all known to
be able to work together such that the device can be caused to enter
(and later leave) reduced-power bus mode.

[Jan Axelson]

The two power utilities I'm aware of are

pwrtest in the WDK under Tools\x86\ and Tools\x64\, see the Disk Scenario

and

powercfg included with Windows

[chsdkj]

I've since learned that there is as well the Microsoft USBLPM utility.

Thanks!

[Jan Axelson]

Yes, that's another good one!

[chsdkj]

In using USBLPM on a Windows 8.1 desktop with various off-the-shelf PCIe USB3 controller cards and USB3 peripherals (hard and thumb drives, and USB hubs), I'm getting peculiar results, such as the U0 power state not being reported for the peripherals when one controller is used, and the inability of the USBLPM utility to cause any of the peripherals under any of the controllers to successfully enter and exit any reduced-power (U1 or U2) state.

Have you any suggestions or contact information for someone who might be thoroughly knowledgeable regarding the ins and out of the USBLPM utility, or how to troubleshoot the situation?

[Jan Axelson]

You could try the Microsoft forum:

http://msdn.microsoft.com/en-US/windows/hardware/gg454517