Re: [PATCH v3 1/2] usb: core: clean up before handing a device to the generic driver

[sashiko-bot@kernel.org]

> When a USB device driver's probe returns -ENODEV, usb_probe_device()
> hands the device to the generic driver. It does not first undo what it
> did before calling the probe. This causes two problems.
> 
> First, if the driver sets generic_subclass, the generic probe has
> already run. It configured the device and sent a USB_DEVICE_ADD
> notification. The generic driver then does both again. Notifier users
> such as the usbport LED trigger see two USB_DEVICE_ADDs with no
> USB_DEVICE_REMOVE in between.
> 
> Second, if the driver does not set supports_autosuspend, a runtime PM
> reference was taken before the probe. Nothing drops it, so the device
> can never be runtime suspended.
> 
> Clean up before handing the device over, in the same way as
> [ ... ]
> driver can't be resumed. Its USB_DEVICE_ADD stays unpaired, because
> sending USB_DEVICE_REMOVE would mean unconfiguring the device.
> 
> Fixes: 88b7381a939d ("USB: Select better matching USB drivers when available")
> Signed-off-by: James Clark <jjc@jclark.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/cover.1793669297.git.jjc@jclark.com?part=1