Re: [2.6.22-rc1-mm1] vaio laptop (SZ72B) immediately resumes after STR

David Brownell
2007-06-22T10:08:25Z

On Wednesday 20 June 2007, Rafael J. Wysocki wrote:

> Well, there's nothing interesting in there, AFAICS:
>
> Device S-state Status Sysfs node
> P0P4 S4 disabled pci:0000:00:1e.0
> BNIC S4 disabled pci:0000:02:05.0
> USB1 S4 disabled pci:0000:00:1d.0
> USB2 S4 disabled pci:0000:00:1d.1
> USB3 S4 disabled pci:0000:00:1d.2
> EUSB S4 disabled pci:0000:00:1d.7
> PS2K S4 disabled pnp:00:0b
> PS2M S4 disabled pnp:00:0c

The interesting thing there is that all those devices are
able to wake from S4 state ... including USB controllers.

That's not very common for USB. EHCI ("EUSB" above) at
least has a spec for how that should work ... it relies on
the PCI Vaux power well to maintain power sessions, though
I don't know that the EHCI code has been tested against
that part of the spec. UHCI likely relies on black magic
to achieve that effect.

- Dave