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From: Clint on 8 Sep 2006 15:22
I'm using the microchip custom firmware with my USB device and I'm
having problems with the the computer constantly trying to suspend the
device. It makes the device respond slowly and sporadically. When I
uncheck the box "Allow the computer to turn this device off to save
power" in the Power Management tab of the device in the device manager,
the device works much better.

Is there any way in the device descriptor or inf file to tell the
computer it shouldn't be trying to shut this device down constantly?
Or do I need to make a WMI call as part of the driver install to
uncheck that check box?

Any help is appreciated.

Thanks,
Clint

From: Vetzak on 9 Sep 2006 06:20

Are you using a system driver are a custom driver? A.f.a.i.k. Most
system drivers don't support selective suspend (for example, USB
sticks).


Clint wrote:
> I'm using the microchip custom firmware with my USB device and I'm
> having problems with the the computer constantly trying to suspend the
> device. It makes the device respond slowly and sporadically. When I
> uncheck the box "Allow the computer to turn this device off to save
> power" in the Power Management tab of the device in the device manager,
> the device works much better.
>
> Is there any way in the device descriptor or inf file to tell the
> computer it shouldn't be trying to shut this device down constantly?
> Or do I need to make a WMI call as part of the driver install to
> uncheck that check box?
>
> Any help is appreciated.
>
> Thanks,
> Clint

From: Vetzak on 9 Sep 2006 06:20

Are you using a system driver are a custom driver? A.f.a.i.k. Most
system drivers don't support selective suspend (for example, USB
sticks).


Clint wrote:
> I'm using the microchip custom firmware with my USB device and I'm
> having problems with the the computer constantly trying to suspend the
> device. It makes the device respond slowly and sporadically. When I
> uncheck the box "Allow the computer to turn this device off to save
> power" in the Power Management tab of the device in the device manager,
> the device works much better.
>
> Is there any way in the device descriptor or inf file to tell the
> computer it shouldn't be trying to shut this device down constantly?
> Or do I need to make a WMI call as part of the driver install to
> uncheck that check box?
>
> Any help is appreciated.
>
> Thanks,
> Clint

From: Clint on 11 Sep 2006 10:41
Vetzak,
I'm using a custom driver.

Any ideas how a custom driver indicates it doesn't support selective
suspend?

Thanks,
Clint

Vetzak wrote:
> Are you using a system driver are a custom driver? A.f.a.i.k. Most
> system drivers don't support selective suspend (for example, USB
> sticks).

From: Vetzak on 12 Sep 2006 07:24

Your driver decides when the device goes in and out USB selective
suspend. To do so, your driver has to send down the wait-wake power IRP
and then the IOCTL_INTERNAL_USB_SUBMIT_IDLE_NOTIFICATION IRP (see ddk
docs and USB samples driver sources for details on these mechanisms).

If you don't want USB selective suspend, just don't implement it in
your driver. Also beware of the state of the "remote wake-up enable"
bit in the USB configuration descriptor. If set, the USBD will activate
RWU on te device, else it won't. Your driver doesn't send that
SetFeature, REMOTE_WAKEUP control request.

One more remark: USB selective suspend in WinXP sucks. Examples:
* The MS information sources are confusing. First they said selective
suspend wasn't supported for composite devices, afterwards tey said it
is. In my experience selective suspend doesn't work properly on all
systems. That's why we converted our composite devices into
non-composite devices and wrote bus drivers.
* The power mappings of root hubs are often wrong leading to strange
behavior after standby and resume (like the system disconnects USB
device but the driver isn't surprise-removed). Example wrong mapping:
S0->D0, S1->D2, S2->D3, S3->D2, S3->D3, S4->D2, S5->D3.
* If you manage to suspend a USB device, and connect a second device to
the same (root) hub, the selective suspend is cancelled on the first
one. So no selective suspend if 2 or more usb device are connected to
the same (root) hub.

I hope I didn't take the fun away ;-)


Clint wrote:
> Vetzak,
> I'm using a custom driver.
>
> Any ideas how a custom driver indicates it doesn't support selective
> suspend?
>
> Thanks,
> Clint
>
> Vetzak wrote:
> > Are you using a system driver are a custom driver? A.f.a.i.k. Most
> > system drivers don't support selective suspend (for example, USB
> > sticks).

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