On Wed, 15 Apr 2009, Eric Miao wrote:
> From a0e1b72f073f4b3dd811b6c4fe4cae4044e56d45 Mon Sep 17 00:00:00 2001
> From: Yong Yao <yaoyong@xxxxxxxxxxx>
> Date: Wed, 15 Apr 2009 13:08:56 +0800
> Subject: [PATCH] usb core: HNP support in hub.c
>
> When starting HNP, we need reset the port, so USB_PORT_STAT_ENABLE is
> set. In such case, we should not disable the port, otherwise the port
> will be disconnected. It will cause that HNP to fail, since the state
> machine will change from OTG_STATE_B_HOST to OTG_STATE_B_PERIPHERAL
> after the port is disconnected.
>
> Signed-off-by: Yong Yao <yaoyong@xxxxxxxxxxx>
> Signed-off-by: Eric Miao <eric.miao@xxxxxxxxxxx>
> ---
>
> Alan, this is a follow-up of the previous thread, with the fix
> to be OTG specific, please help review.
>
> drivers/usb/core/hub.c | 7 +++++--
> 1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index b19cbfc..2e28f48 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -688,8 +688,11 @@ static void hub_activate(struct usb_hub *hub,
> enum hub_activation_type type)
> * Unconnected ports should likewise be disabled (paranoia),
> * and so should ports for which we have no usb_device.
> */
> - if ((portstatus & USB_PORT_STAT_ENABLE) && (
> - type != HUB_RESUME ||
> + if ((portstatus & USB_PORT_STAT_ENABLE) &&
> +#ifdef CONFIG_USB_OTG
> + !(hdev->bus->is_b_host) &&
> +#endif
> + (type != HUB_RESUME ||
> !(portstatus & USB_PORT_STAT_CONNECTION) ||
> !udev ||
> udev->state == USB_STATE_NOTATTACHED)) {
This is a lot better than the previous patch. I wonder if there is a
simple way to eliminate the ugly preprocessor test. For instance, if
CONFIG_USB_OTG isn't defined, won't hdev->bus->is_b_host always be 0?
I also wonder if this is truly correct. Evidently you want the new
behavior to apply during the HNP exchange, but what about at other
times? Suppose the device is already a B-host when its root hub gets
suspended; what would happen then?
Alan Stern
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