Re: [RFC 3/3] net: cdc_ncm: Add ACPI MAC address pass through functionality

["Bjørn Mork" <bjorn@mork.no>]

<Charles.Hyde@dellteam.com> writes:

> +static int cdc_ncm_resume (struct usb_interface *intf)
> +{
> +	struct usbnet *dev = usb_get_intfdata(intf);
> +	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
> +	int ret;
> +
> +	ret = usbnet_resume(intf);
> +	if (ret != 0)
> +		goto error2;
> +
> +	if (ctx->ether_desc) {
> +		struct sockaddr sa;
> +
> +		if (cdc_ncm_get_ethernet_address(dev, ctx)) {
> +			dev_dbg(&intf->dev, "failed to get mac address\n");
> +			goto error2;
> +		}
> +		if (get_acpi_mac_passthru(&intf->dev, &sa) == 0) {
> +			if (memcmp(dev->net->dev_addr, sa.sa_data, ETH_ALEN) != 0) {
> +				if (cdc_ncm_set_ethernet_address(dev, &sa) == 0) {
> +					memcpy(dev->net->dev_addr, sa.sa_data, ETH_ALEN);
> +				}
> +			}
> +		}
> +		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
> +	}
> +
> +error2:
> +	return ret;
> +}


This is wrong.  dev->net->dev_addr will hold the correct address, and it
does not have to match any USB descriptor or ACPI table entry. It's a
user managed address.

You should simply make sure the device is syncronized with the
dev->net->dev_addr field.  But you probably want to avoid doing that if
it failed initially.  There is no need to issue control requests you
know will fail.

Why the dev_info()? It logs info the user can retrieve with a simple
"ip link" or similar.  Seems pretty useless even as a debug statement?


Bjørn