Re: [RFC] USB: driver for iphone charging

[Oliver Neukum <oliver@neukum.org>]

Am Freitag 24 August 2007 schrieb Greg KH:

Hi,

> +static int select_configuration(struct usb_device *udev)
> +{
> +       char *dummy_buffer = kzalloc(2, GFP_KERNEL);
> +       int retval;
> +
> +       if (!dummy_buffer)
> +               return -ENOMEM;
> +
> +       dbg(&udev->dev, "Calling set_configuration\n");
> +       retval = usb_driver_set_configuration(udev, 3);
> +       if (retval) {
> +               dev_err(&udev->dev, "Set Configuration failed :%d.\n", retval);
> +               goto exit;
> +       }
> +
> +       dbg(&udev->dev, "Sending first magic command\n");
> +       retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x40, 0x40,
> +                                0x6400, 0, dummy_buffer, 0, 100);
> +

int usb_driver_set_configuration(struct usb_device *udev, int config)
{
	struct set_config_request *req;

	req = kmalloc(sizeof(*req), GFP_KERNEL);
	if (!req)
		return -ENOMEM;
	req->udev = udev;
	req->config = config;
	INIT_WORK(&req->work, driver_set_config_work);

	usb_get_dev(udev);
	schedule_work(&req->work);
	return 0;
}

This schedules the change via a workqueue, so you'll be reprobed. If you
fire of the first vendor command you are doing so before the configuration
is changed. How is this supposed to work?

	Regards
		Oliver