Re: Check if usb device is suspended

From: Jagdish Gedia
Date: Fri Mar 21 2014 - 07:47:21 EST

I want to resume the usb device on some event, so i want to check if
it is suspended. I think by above method i can check if the device is
already suspended, but may be i will miss to resume the device if it
is suspending. Is there any way through which i can check if device is

On Thu, Mar 13, 2014 at 7:50 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 13 Mar 2014, Jagdish Gedia wrote:
>> Hi,
>> I want to check in my driver if usb device is suspended or not?
> Why do you need to check? Your driver gets told every time the device
> suspends and every time it resumes. Therefore it should already know
> the answer.
>> currently i am doing it like
>> if(udev->state==USB_STATE_SUSPENDED)
>> Is this the proper way? Is this enough?
> Aside from the fact that the device's state may change immediately
> after you make this test, as Oliver pointed out, you also should
> realize that this test might not give the correct answer if the device
> is in the middle of suspending or resuming when the test runs.
> Alan Stern
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