On Wed, 18 Oct 2017, Daniel Drake wrote:
> When going into S3 suspend, the Acer TravelMate P648-M and P648-G3
> laptops immediately wake up 3-4 seconds later for no obvious reason.
>
> Unbinding the integrated Huawei 4G LTE modem before suspend avoids
> the issue, even though we are not using the modem at all (checked
> from rescue.target/runlevel1). The problem also occurs when the option
> and cdc-ether modem drivers aren't loaded; it reproduces just with the
> base usb driver. Under Windows the system can suspend fine.
>
> Seeking a better fix, we've tried a lot of things, including:
> - Check that the device's power/wakeup is disabled
> - Check that remote wakeup is off at the USB level
> - All the quirks in drivers/usb/core/quirks.c e.g. USB_QUIRK_RESET_RESUME,
> USB_QUIRK_RESET, USB_QUIRK_IGNORE_REMOTE_WAKEUP, USB_QUIRK_NO_LPM.
>
> but none of that makes any difference.
>
> There are no errors in the logs showing any suspend/resume-related issues.
> When the system wakes up due to the modem, log-wise it appears to be a
> normal resume.
>
> Introduce a quirk to disable the port during suspend when the modem is
> detected.
...
> Based on an earlier patch by Chris Chiu.
>
> Signed-off-by: Daniel Drake <drake@xxxxxxxxxxxx>
> ---
>
> Notes:
> v2:
> - Handle quirk later in suspend, to avoid interfering with other parts
> of the suspend routine.
> - Don't do the disconnect on runtime suspend, only for S3 suspend
>
> v3:
> - Ignore return value from usb_port_disable()
> - Correct kerneldoc Context information
> - Don't mark device as disconnected
>
> drivers/usb/core/driver.c | 10 +++++++++-
> drivers/usb/core/hub.c | 13 +++++++++++++
> drivers/usb/core/quirks.c | 6 ++++++
> drivers/usb/core/usb.h | 1 +
> include/linux/usb/quirks.h | 6 ++++++
> 5 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
> index eb87a259d55c..353993f983c8 100644
> --- a/drivers/usb/core/driver.c
> +++ b/drivers/usb/core/driver.c
> @@ -1461,6 +1461,7 @@ static void choose_wakeup(struct usb_device *udev, pm_message_t msg)
> int usb_suspend(struct device *dev, pm_message_t msg)
> {
> struct usb_device *udev = to_usb_device(dev);
> + int r;
>
> unbind_no_pm_drivers_interfaces(udev);
>
> @@ -1469,7 +1470,14 @@ int usb_suspend(struct device *dev, pm_message_t msg)
> * so we may still need to unbind and rebind upon resume
> */
> choose_wakeup(udev, msg);
> - return usb_suspend_both(udev, msg);
> + r = usb_suspend_both(udev, msg);
> + if (r)
> + return r;
> +
> + if (udev->quirks & USB_QUIRK_DISCONNECT_SUSPEND)
> + usb_port_disable(udev);
> +
> + return 0;
> }
Bikeshedding: I would write this as:
if (r == 0 && (udev->quirks & USB_QUIRK_DISCONNECT_SUSPEND))
usb_port_disable(udev);
return r;
But it doesn't matter; the compiler probably will generate the same
code either way. In any case:
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Alan Stern
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