On Fri, Mar 09, 2001, Grover, Andrew <[EMAIL PROTECTED]> wrote:
> > This wouldn't work for systems with builtin hubs (not the
> > root hub) and
> > just doesn't seem very intuitive to me.
> >
> > I'm not super familiar with the steps ACPI goes through to
> > suspend, but
> > don't we have a warning that a suspend is about to happen and
> > we can do
> > things?
> >
> > Wouldn't this be a better time to suspend the HC?
>
> I am not talking about suspending the HC when the system is suspended, I am
> talking about suspending the HC when *the system is running* and no devices
> are attached.
>
> Why bother? Because running the HC even with nothing attached prevents ACPI
> from putting the CPU into deep sleep (C3) when idle. The HC is not only
> wasting power, it is causing the CPU to waste power.
>
> We will also want to suspend the HC (even with devices attached) when the
> system goes to sleep, but I was focussing on the other issue first.
Ahh, then this is tricky. This sounds like the best we can do for now
then.
It's unfortunately not perfect.
> I am not a USB expert -- how would builtin hubs complicate things?
It's just like any other device, it would generate traffic. This is not
the same as the root hub (which all HC's have are not a "real" device)
and not all HC's have builtin hub's, but I'm seeing them more often now.
JE
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
http://lists.sourceforge.net/lists/listinfo/linux-usb-devel
