I made some experiments and it seems USB device is marked as “bad” when it generates remote wakeup too soon after USB suspend when system is going to low power mode. The boundary time is about 30 ms (maybe more because there is firmware overhead which is hard to measure). When remote wakeup is generated sooner, device doesn’t work after OS resume and USB Root Hub device has to be disabled/enabled to recover. It seems as OS disables given port. When it is generated a bit later, remote wakeup doesn’t work during suspend but device works normally after OS resume.
USB mouse behaves the same way; when I click rapidly during OS suspend, mouse can’t wake it. I wasn’t able to make mouse non-functional as I’m probably unable to click so fast 
Well, it seems there are rules which device should follow. No problem to change firmware accordingly but are these rules documented? I’m almost sure it didn’t work that way until XP SP2. Could anybody from MS tell me how exactly it works and how is device expected to behave? Thanks.
Best regards,
Michal Vodicka
UPEK, Inc.
[xxxxx@upek.com, http://www.upek.com]
From: xxxxx@lists.osr.com[SMTP:xxxxx@lists.osr.com] on behalf of Michal Vodicka[SMTP:xxxxx@upek.com]
Reply To: Windows System Software Devs Interest List
Sent: Thursday, November 04, 2004 5:33 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Remote wakeup during suspend
We have an USB device which uses remote wakeup to signal some event and wake up suspended system. Works well but if remote wakeup is generated just in the moment when OS goes into suspend, it isn’t awakened and later after resume device is in non-functional state. No surprise removal but every IRP sent down the stack returns STATUS_DEVICE_NOT_CONNECTED. The only way how to recover is to disable/enable USB Root Hub device to which it is attached. Or reboot, of course.
It seems as the new XP SP2 feature. Can anybody confirm it? Is there some solution of this problem? I can’t stop device from generating remote wakeup as it is reaction to an external event (user puts finger on sensor).
Best regards,
Michal Vodicka
UPEK, Inc.
[xxxxx@upek.com, http://www.upek.com]
Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256
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