On Tue, 11 Dec 2012, Lan Tianyu wrote:

> Hi Alan&Greg:
>           Since 3.1, Alan enabled usb device wakeup default, there are
> a lot of problem that immediately resume when enter into s2ram/s2disk.
> I have traced some these bugs. Most of these bugs are related usb1.1
> device which attached to OHCI/UHCI. If disable the hc wakeup or no device
> attached, it will work again. Not all usb1.1 devices will cause this issue.

What if the device is disabled for wakeup?  That's the right solution 
if the device is buggy.

>          From enabe/disable hc wakeup side, I check what is done in the ACPI.
> When system is entering into s3/s4, ACPI will check all the device which has
> wakeup resource(there is  a gpe interrupt for these devices). If their
> wakeup was
> enabled, ACPI will enable their gpe interrupt . If there was a signal of gpe
> during s3, the system would be resumed.

That's the right thing to do.

>         Normally, usb hc will have gpe to wakeup system. This issue caused by
> hc with some usb1.1 devices triggering wakeup signal just after
> entering into s3/s4.

Does the HC turn on the GPE even when the device does not send a remote 
wakeup request?

Does the device send a remote wakeup request even when it is disabled 
for remote wakeup?

> System resumes immediately. Since the signal is triggered after system 
> entering
> into s3/s4, it's hard to debug what hc does during this procedure(This
> comes from
> my analyse, I have no such machine to debug).
>         So can we add a blacklist which contains devices causing such
> issue and disable
> these devices' remote wakeup  when system suspend  to avoid such
> problems?

Well, we can create blacklist entries for malfunctioning USB devices.  
I don't know about malfunctioning host controllers, though.  Maybe.

> Or you
> have some new debug measures, they are welcome. If something I said is
> wrong, please
> help me correct it. Thanks.

We really need to know which component is bad: the host controller or 
the device.

Alan Stern


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