2006-10-08 08:39:18

by Oliver Neukum

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Subject: Re: [linux-usb-devel] error to be returned while suspended

Am Sonntag, 8. Oktober 2006 09:20 schrieb David Brownell:
> > If a device is always opened, as mice are, it will not be suspended.
> > Yet they can be without any data to deliver forever.
>
> In 2.6.19-rc1 read Documentation/power/devices.txt about runtime
> suspend states. ?Then think about how why mouse in a runtime suspend
> state, with remote wakeup enabled, looks externally ** EXACTLY ** like
> a mouse that's fully active ....

I've done so. And I've read the HID spec. It just says that a mouse
may support remote wakeup, not what should wake it up. A device
that wakes only if a button is clicked is within spec.

Regards
Oliver


2006-10-08 14:16:49

by Dmitry Torokhov

[permalink] [raw]
Subject: Re: [linux-usb-devel] error to be returned while suspended

On Sunday 08 October 2006 04:39, Oliver Neukum wrote:
> Am Sonntag, 8. Oktober 2006 09:20 schrieb David Brownell:
> > > If a device is always opened, as mice are, it will not be suspended.
> > > Yet they can be without any data to deliver forever.
> >
> > In 2.6.19-rc1 read Documentation/power/devices.txt about runtime
> > suspend states. ?Then think about how why mouse in a runtime suspend
> > state, with remote wakeup enabled, looks externally ** EXACTLY ** like
> > a mouse that's fully active ....
>
> I've done so. And I've read the HID spec. It just says that a mouse
> may support remote wakeup, not what should wake it up. A device
> that wakes only if a button is clicked is within spec.
>

And that's what some devices do. Apologies for a non-USB example, but
since we are talking about input devices and it would be nice to have
the rules consistent across all hardware interfaces I think it's OK...
Synaptics PS/2 touchpad can be put into a sleep mode where it only
reacts on button presses. While this behavior is reasonable for system-
wide suspend it would hardly work for autosuspend.

--
Dmitry