On Wed, Dec 08, 2021 at 05:39:51PM +0800, Yinbo Zhu wrote:
> The remote wake up function is a regular function on usb device and
> I think keeping it enabled by default will make the usb application
> more convenient and usb device remote wake up function keep enabled
> that ask usb controller remote wake up was enabled at first.
>
> This patch only enable wake up on usb root hub device, among which,
You say the patch only affects root hub devices, but this doesn't appear
to be true.
> usb3.0 root hub doesn't be set wakeup node property but use command
> USB_INTRF_FUNC_SUSPEND to enable remote wake up function.
>
> Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 20 ++++++++++++++++++--
> include/linux/usb.h | 4 +++-
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 86658a8..cb4b956 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -2509,6 +2509,8 @@ static void set_usb_port_removable(struct usb_device *udev)
> */
> int usb_new_device(struct usb_device *udev)
> {
> + struct usb_host_config *config;
> + int ncfg;
> int err;
>
> if (udev->parent) {
> @@ -2540,6 +2542,18 @@ int usb_new_device(struct usb_device *udev)
> udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
> (((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
>
> + for (ncfg = 0; ncfg < udev->descriptor.bNumConfigurations; ncfg++) {
> + config = &udev->config[ncfg];
> + if ((config->desc.bmAttributes & (1 << 5)) == 0)
> + break;
> + if (ncfg + 1 == udev->descriptor.bNumConfigurations) {
> + err = usb_enable_remote_wakeup(udev);
> + if (err)
> + dev_dbg(&udev->dev,
> + "won't remote wakeup, err %d\n", err);
> + }
> + }
I don't see anything in there which treats root hubs differently from
other devices.
Besides, enabling wakeup for root hubs is generally a bad idea. Suppose
you closed a laptop's lid and then unplugged a USB device -- with wakeup
enabled, the unplug would cause the laptop to wake up again without your
knowledge.
Alan Stern
