On Wed, 24 May 2017, Kai-Heng Feng wrote:
> On Wed, May 24, 2017 at 12:43 AM, Alan Stern <[email protected]>
> wrote:
> >>
> >> Output of `cat /sys/kernel/debug/usb/usbmon/1u`:
> >> Runtime PM disabled as attachment.
> >
> > When you say "runtime PM disabled", you mean that it is disabled for
> > the EHCI controller but enabled for other devices, right?
>
> Yes, disabled for the ehci-hcd. Runtime PM is enabled for ehci-pci.
>
> >
> >> It's empty when runtime PM is enabled.
> >
> > And nothing shows up in the dmesg log either? This suggests that the
> > PME signal isn't working properly.
> >
> > Try doing this: With runtime PM enabled, plug in a device. When
> > nothing happens, do:
> >
> > lspci -v -s 00:12.0
> >
> > The output should show whether the controller is sending a wakeup
> > signal. Does it cause the device to be detected?
>
> No.
>
> 00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB
> EHCI Controller (rev 39) (prog-if 20 [EHCI])
> Subsystem: Dell FCH USB EHCI Controller
> Flags: 66MHz, medium devsel, IRQ 18
> Memory at fe769000 (32-bit, non-prefetchable) [size=256]
> Capabilities: [c0] Power Management version 2
> Capabilities: [e4] Debug port: BAR=1 offset=00e0
> Kernel driver in use: ehci-pci
>
> > If it doesn't, run lsusb. That definitely should wake up the
> > controller and cause the device to be detected. Then run the lspci
> > command again. Let's see what the output from these commands shows.
>
> I plugged an optical mouse to test:
> lsusb or "lsusb -s 001:001" does nothing, the mouse is not shown in
> lsusb. The optical light is off.
> "lsusb -s 001:001 -v" wakes up the controller and make the mouse to be
> detected, the mouse is in lsusb and works correctly.
> Once I turned on runtime PM on the mouse, it no longer works. The
> optical light is still on but it did not response to movement or
> click.
>
> This is the lspci right after I use "lsusb -s 001:001 -v" to wake up
> the controller:
> 00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB
> EHCI Controller (rev 39) (prog-if 20 [EHCI])
> Subsystem: Dell FCH USB EHCI Controller
> Flags: bus master, 66MHz, medium devsel, latency 32, IRQ 18
> Memory at fe769000 (32-bit, non-prefetchable) [size=256]
> Capabilities: [c0] Power Management version 2
> Capabilities: [e4] Debug port: BAR=1 offset=00e0
> Kernel driver in use: ehci-pci
My mistake; we need to see the information from "lspci -vv -s 00:12.0"
with two "v"'s, not just one.
There's another piece of information you can collect. Mount a
debugfs filesystem at /sys/kernel/debug, and then copy the contents of
the file
/sys/kernel/debug/usb/ehci/0000:00:12.0/registers
Do this while the controller is still asleep (after the mouse is
plugged in) and then again after it is awake.
Alan Stern
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