Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Alan Stern <stern@rowland.harvard.edu>]

On Sat, 13 Mar 2010, Bruno [UTF-8] Prémont wrote:

> Is something like below acceptable? (from error handling point of view
> it makes no difference...)
> 
> Thanks,
> Bruno
> 
> file: drivers/hid/hid-core.c
> 
>  int hid_add_device(struct hid_device *hdev)
>  {
>          static atomic_t id = ATOMIC_INIT(0);
>          int ret;
>  
>          if (WARN_ON(hdev->status & HID_STAT_ADDED))
>                  return -EBUSY;
>  
>          /* we need to kill them here, otherwise they will stay allocated to
>           * wait for coming driver */
>          if (hid_ignore(hdev))
>                  return -ENODEV;
>  
>          /* XXX hack, any other cleaner solution after the driver core
>           * is converted to allow more than 20 bytes as the device name? */
>          dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
>                       hdev->vendor, hdev->product, atomic_inc_return(&id));
>  
> +        hid_debug_register(hdev, dev_name(&hdev->dev));
>          ret = device_add(&hdev->dev);
>          if (!ret)
>                  hdev->status |= HID_STAT_ADDED;
>  
> -        hid_debug_register(hdev, dev_name(&hdev->dev));
>  
>          return ret;
>  }

If the device_add() fails, you should undo the hid_debug_register() 
call.

Alan Stern