On Fri, 20 May 2011, Libor Pechacek wrote:
> Protocol stall should not be fatal while reading port or hub status as it is
> transient state. Currently hub EP0 STALL during port status read results in
> failed device enumeration. This has been observed with ST-Ericsson (formerly
> Philips) USB 2.0 Hub (04cc:1521) after connecting keyboard.
Hmmm. The USB spec says that a device is supposed to send a protocol
stall when the request isn't supported or the device has an error.
Neither should be true in this case.
But what can we do if the ST-Ericsson hub wants to be non-compliant...
> Signed-off-by: Libor Pechacek <lpechacek@xxxxxxx>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> This in fact extends the logic introduced by Alan in 645ff95d (USB: Hub driver:
> improve error checking and retries [10/13]).
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 93720bd..78e7f25 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -339,7 +339,8 @@ static int get_hub_status(struct usb_device *hdev,
> {
> int i, status = -ETIMEDOUT;
>
> - for (i = 0; i < USB_STS_RETRIES && status == -ETIMEDOUT; i++) {
> + for (i = 0; i < USB_STS_RETRIES &&
> + (status == -ETIMEDOUT || status == -EPIPE); i++) {
> status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
> USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
> data, sizeof(*data), USB_STS_TIMEOUT);
> @@ -355,7 +356,8 @@ static int get_port_status(struct usb_device *hdev, int port1,
> {
> int i, status = -ETIMEDOUT;
>
> - for (i = 0; i < USB_STS_RETRIES && status == -ETIMEDOUT; i++) {
> + for (i = 0; i < USB_STS_RETRIES &&
> + (status == -ETIMEDOUT || status == -EPIPE); i++) {
> status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
> USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port1,
> data, sizeof(*data), USB_STS_TIMEOUT);
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Alan Stern
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