Re: [PATCH v1 2/2] usb: core: enable remote wakeup function for usb controller
From: Alan Stern <stern@rowland.harvard.edu>
Date: 2021-12-08 22:05:01
Also in:
linux-input, lkml
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.
quoted hunk ↗ jump to hunk
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@loongson.cn> --- 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