Subject: Re: [PATCH] cxacru: ignore cx82310_eth devices

From: Greg KH <[email-masked]>
Date: Sat, 4 Sep 2010 21:03:52 -0700

On Sat, Sep 04, 2010 at 05:30:20PM +0100, Simon Arlott wrote:
> Ignore ADSL routers, which can have the same vendor and product IDs
> as ADSL modems but should be handled by the cx82310_eth driver.
> 
> This intentionally ignores device IDs that aren't currently handled
> by cx82310_eth. There may be other device IDs that perhaps shouldn't
> be claimed by cxacru.
> 
> Signed-off-by: Ondrej Zary <[email-masked]>
> [SA: Moved to cxacru_usb_probe, message level lowered to info]
> Signed-off-by: Simon Arlott <[email-masked]>
> ---
>  drivers/usb/atm/cxacru.c |   18 ++++++++++++++++--
>  1 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
> index 593fc5e..96fa736 100644
> --- a/drivers/usb/atm/cxacru.c
> +++ b/drivers/usb/atm/cxacru.c
> @@ -1324,8 +1324,22 @@ static struct usbatm_driver cxacru_driver = {
>  	.tx_padding	= 11,
>  };
>  
> -static int cxacru_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
> -{
> +static int cxacru_usb_probe(struct usb_interface *intf,
> +		const struct usb_device_id *id) {
> +	struct usb_device *usb_dev = interface_to_usbdev(intf);
> +	char buf[15];
> +
> +	/* avoid ADSL routers (cx82310_eth)
> +	 * abort if bDeviceClass is 0xff and iProduct is "USB NET CARD" */
> +	if (usb_dev->descriptor.bDeviceClass == 0xff

vendor class?  We have a macro for that?

> +			&& usb_dev->descriptor.iProduct

Almost everyone has a iProduct, right?  Why even test for that?

> +			&& usb_string(usb_dev,
> +				usb_dev->descriptor.iProduct, buf, sizeof(buf))

usb_string() should handle a 0 string, right?

> +			&& !strcmp(buf, "USB NET CARD")) {

Just to make it a bit easier to follow, how about you do the
usb_string() call in the if statment, and then compare the string and
then, if that matches you do:

> +		dev_info(&intf->dev, "ignoring cx82310_eth device\n");
> +		return -ENODEV;

Well, actually, dev_info?  I guess so, but do you really want to see
this message every time?

thanks,

greg k-h