I just thought I'd provide a quick update on the state of USB PM,
at least according to my testing(*) after the patches that are now
in Greg's 2.6.15 queue(**) ... I just forwarded the patch overviews
to this list, the details are on linux-usb-devel.
- Suspend/resume of the PCI devices through sysfs behaves again ...
it seems to have broken badly sometime after 2.6.10 or 2.6.11
- Likewise it behaves through swsusp "shutdown/reboot", both with
and without devices attached.
- I have one system on which S1 suspend/resume works, at
least if I use PS/2 keyboard to trigger wakeup.
- On some other systems, both S1 and S3 suspend fail; the
system dies in ACPI during wakeup processing.
As for remote wakeup, using a USB keyboard, that still looks OK
(no regressions needed fixing) except when ACPI kicks in:
- For "runtime PM" scenarios where individual devices and
hubs (including root hubs) are suspended, the relevant
parts of the device tree wake up just fine.
- For "system PM" scenarios, and with /proc/acpi/wakeup
tweaked to enable all wakeup events, mixed results:
* The system where S1 works seems to run into some
ACPI bugs; the last messages relate to overflow,
evidently the wakeup signal is never acknowledged.
* Those other systems don't have any better luck
when the S1/S3 resume signal is a USB wakeup than
any other kind of wakeup.
Compared to the last time I tested this, it's good to at least
see the USB remote wakeup signals waking the system up; those
seem to be ACPI improvements. But it still looks like the
cases I most want to see working (S1, S3) are failing on PCs.
There are a few small USB PM updates on the way from me (call
it all cleanups), and Alan's planning some updates too.
- Dave
(*) EHCI and OHCI only; no UHCI boxes.
(**) http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
