On Tue, Nov 1, 2011 at 3:28 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
>
> The fact that you see the EHCI "resume" messages with commit 379021d5c0 applied
> means that the EHCI really does have the PME Status bit set when it's being
> polled, because the resume wouldn't be triggered otherwise.
I don't think that is true.
> So, it _seems_ like plugging the USB device into the xHCI port causes the EHCI's
> PME Status bit to be set as well.
I suspect that runtime-PM is doing something wrong, because I can not
confirm that at all.
> You can try to confirm this by looking at the PME Status bits of the
> devices in question under 3.1 (ie. without commit 379021d5c0) before
> (they should be unset) and after plugging in the USB device (the xHCI's PME
> status should be set, the EHCI's one may or may not be set). Simply look at
> the status line under the PM capability in the output of "lspci -vv" for
> each interesting device.
No. In 3.1, the *only* device with "PME+" is the NEC XHCI controller.
An no dmesg entries or anything. There does seem to be ACPI interrupts
happening, although I do not know whether they really were related to
the USB insertion event.
> I wonder if plugging a device into a known non-xHCI USB port triggers any
> events with plain 3.1?
Yes. Plugging something into the other USB port (which I originally
didn't even realize is a USB port at all: I think it's an eSATA port
as well) works.
But it shows similar crazy "cross-talk" issues: when that event
happens, *both* ehci controllers get woken up, *and* the xhci
controller does too.
I really think there is something wrong in the PM code. I do believe
that there could be a BIOS issue too (let me be on record - for the
millionth time - as saying that BIOS coders are monkeys on crack and
to basically expect all firmware to be broken by default), but see
above: the hardware isn't *that* broken. The PME+ status really only
happened for the XHCI controller when I plugged in the USB cable in
there. So the fact that current git will chatter about all those other
controllers means that there must be paths that do *not* check PME.
Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
