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From: Zhu Xiaolin<zhuxl@v...>
Date: Mon Aug 22 05:27:52 CEST 2005
Subject: [usb] 4ms SE0
Hi,

When I test a device when system suspend/hibernate ~ resume, sometime
I find on D+/D- a SE0 pulse between long suspend. The SE0 pulse is longer
than 2.5us and shorter than 10ms, usually, it is 4ms.

I think according the 7.1.7.5 of USB2.0 spec, SE0 which is longer than 2.5us
should be a usb reset. And the reset signal must be longer than 10ms. So the
4ms SE0 is not a valid signal. Is it correct?

And it seems the 4ms SE0 doesn't occur everytime during the resume process.
Then what causes the 4ms SE0 happen?

Thanks and best regards,

Zhuxl

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