On Mon, Jun 30, 2008 at 12:16:13PM -0400, Alan Stern wrote:

On Mon, 30 Jun 2008, Dmitry Torokhov wrote:

quoted

quoted

My feeling is that we will leave manual suspension in the kernel.  The
code passed to the USB driver's suspend method will be changed so that
the method can tell whether it is being called for a system sleep vs.
an autosuspend vs. a manual suspend.

Ok, I see... So what does a device do when it is suspended and a
request comes in? Does it automatically resume and service the request
(and potentially goes back to sleep)? Does it queue the request for
later? Ignore it? Is it a system-wide policy or up to the device
[class]?

What sort of request do you mean?  If a device is suspended, it _can't_ 
receive any data (requests or otherwise) over the USB bus.

If a device receives data over some other channel (like a mouse getting
a button click) while it is suspended, its behavior depends on the
settings at the time it was suspended.  If remote wakeup was disabled
then the device does essentially nothing (maybe it remembers the data
for later, maybe not).  If remote wakeup was enabled then the device
should send a wakeup request to the host.

I was talking about system-initiated requests... Setting LED on a keyboard,
setting rate on a mouse, uploading a force-feedback effect, writing a
sector on a disk, etc...

-- 
Dmitry