What does "USB selective suspend" mean?

Question

In Windows 7, Power Options->USB Settings->USB selective suspend setting, what does "USB selective suspend" mean?  Also, given that there is only one setting, why does it say "USB Settings" instead of "USB Setting"?

Answer 1

A USB device driver can send a message to windows telling it to idle the device.  This puts the device in a low-power state (the suspend state).  When a USB device is suspended, windows does not wait for it to respond before entering a sleep or hibernate mode.  If you disable this feature, the system will simply return a failure to the driver when the driver attempts to enter suspend state.  If the driver complies with Microsoft guidelines, it will simply retry the idle request at every expiration of its idle timer.

Answer 2

If anyone is interested in a simplified way to view the Powercfg options and store the results in a .txt file, do the following:

Create a file called 'test.txt' (without quotes)  file on your "Desk Top" and copy the following lines into it.

________________________________________________________________________________

cls

@echo off

echo PowerCfg test written by GXT

echo.

::   Be sure to substitute my user ID GXT with your own user ID

::   the symbols to the left, are the way you created remarks

:: powercfg /l > C:\Users\GXT\Desktop\test.txt

:: powercfg /getactivescheme > C:\Users\GXT\Desktop\test.txt

:: powercfg /lDEVICEQUERY all_devices_verbose > C:\Users\GXT\Desktop\test.txt

powercfg /L > C:\Users\GXT\Desktop\test.txt

pause

exit

_________________________________________________________________________________

Save the data set you just created on your desk top as 'test.BAT'

Now create another dataset on you desk top called 'test.TXT' this will be your output file.

By executing 'test.bat' it will copy the results of PowerCfg into the file named 'test.txt', that you just created the second time.

If you want to save the newly created powercfg listing located in test.txt save it to a different location.

Every time you run  'test.bat' it over writes 'test.txt'

To make changes to test.bat do a right click on it, followed by an EDIT. 

Hope this makes it easier to see what is going on.

PS:

powercfg /? > C:\Users\GXT\Desktop\test.txt

shows all the options available to you (help).

Answer 3

LAPABC, I don't see a previous answer so I will jump in and post what I found while looking into the question you asked.

"So here's the question, do you think that going to Power Options->USB Settings->USB selective suspend and then DISABLING it would have the same effect as what was described above?"

Apparently the answer is yes.  I found that when I disabled suspend in the power settings all of the individual settings on the devices were also disabled.  I don't know if this will have the effect I want, which is to stop my USB devices from being disabled without warning but I am giving it a try.

Answer 4

Google is your friend:

http://www.google.com/search?q=usb+selective+suspend&ie=UTF-8