Re: [PATCH v4] usb: hub: Check device descriptor before resusciation

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Oct 08, 2019 at 10:09:01AM +0200, David Heinzelmann wrote:
> If a device connected to an xHCI host controller disconnects from the USB bus
> and then reconnects, e.g. triggered by a firmware update, then the host
> controller automatically activates the connection and the port is enabled. The
> implementation of hub_port_connect_change() assumes that if the port is
> enabled then nothing has changed. There is no check if the USB descriptors
> have changed. As a result, the kernel's internal copy of the descriptors ends
> up being incorrect and the device doesn't work properly anymore.
> 
> The solution to the problem is for hub_port_connect_change() always to
> check whether the device's descriptors have changed before resuscitating
> an enabled port.
> 
> Signed-off-by: David Heinzelmann <heinzelmann.david@gmail.com>
> ---
> Changes in v4:
>  - changed commit description
> Changes in v3:
>  - changed commit message and description
>  - fix code style
> Changes in v2:
>  - fix logic error to handle return code from usb_get_device_descriptor()
>    properly
>  - fix line endings
> ---
>  drivers/usb/core/hub.c | 196 +++++++++++++++++++++++------------------
>  1 file changed, 111 insertions(+), 85 deletions(-)

What happened to Alan's ack?

v5?

thanks,

greg k-h