Re: power management for usb_hci

Hi Oliver,

> > > Will you post code?
> > 
> > http://git.infradead.org/?p=users/holtmann/bluetooth-drivers.git;a=summary
> > 
> > Look for the the btusb.ko driver.
> 
> +static int btusb_open(struct hci_dev *hdev)
> +{
> +       struct btusb_data *data = hdev->driver_data;
> +       int err;
> +
> +       BT_DBG("%s", hdev->name);
> +
> +       if (test_and_set_bit(HCI_RUNNING, &hdev->flags))
> +               return 0;
> +
> +       if (test_and_set_bit(BTUSB_INTR_RUNNING, &data->flags))
> +               return 0;
> +
> +       err = btusb_submit_intr_urb(hdev);
> +       if (err < 0) {
> +               clear_bit(BTUSB_INTR_RUNNING, &hdev->flags);
> +               clear_bit(HCI_RUNNING, &hdev->flags);
> +       }
> +
> +       return err;
> +}
> 
> That's a race. Furthermore, if btusb_submit_intr_urb() fails, you'll have
> a second open suceeding without a running urb.

that is totally complicated actually since _open() can only start
interrupt URBs anyway. No need to protect against running interrupt URBs
at that point.

Regards

Marcel



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