Re: [RFC] USB: allow new_id to provide driver_info

[Greg KH <greg@xxxxxxxxx>]

On Fri, May 11, 2012 at 11:02:56AM +0200, Bjørn Mork wrote:
> A number of USB drivers are unable to successfully probe a new
> device without some driver specific information in the
> driver_info field. By copying the driver_info from the first
> device in the static device id list, we can enable dynamic
> device IDs for such drivers as well.

Ah, nice hack :)

> This will make the first device a generic template for dynamic
> IDs, with no way to specify another template device.

Is that a real problem?

> Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
> ---
> I'd really like to see some way to make dynamic device IDs work
> for e.g. usbnet based minidrivers. This patch is one way to do
> that.
> 
> Another possibility would be to let the user provide a 
> "template device" from the driver built-in list along with the
> new device ID.  Something like
> 
>  # echo "8086 10f5 8086 10f4" > /sys/bus/usb/drivers/foo/new_id
> 
> where the two last numbers would specify a device already
> supported by the driver. This might be better for drivers with
> a number of different driver_info options, and would also
> provide support for complex class and protocol matching, as long
> as an existing entry has the wanted configuration.
> 
> But it would make it necessary to extend the new_id interface
> yet again, and in a way which cannot easily be combined with the
> recently added interface class match.  Which makes me hesitate...
> 
> Therefore this patch, which is sufficient for most of the
> drivers.
> 
> What do you think?

I like the idea, but I wonder how well this will really work for most
devices.  You say it works for the usbnet drivers, what about others?

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html