RE: [RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through functionality

[<Mario.Limonciello@dell.com>]

> -----Original Message-----
> From: Bjørn Mork <bjorn@mork.no>
> Sent: Saturday, August 24, 2019 5:44 AM
> To: Hyde, Charles - Dell Team
> Cc: linux-usb@vger.kernel.org; linux-acpi@vger.kernel.org;
> gregkh@linuxfoundation.org; Limonciello, Mario; oliver@neukum.org;
> netdev@vger.kernel.org; nic_swsd@realtek.com
> Subject: Re: [RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through
> functionality
> 
> 
> [EXTERNAL EMAIL]
> 
> <Charles.Hyde@dellteam.com> writes:
> 
> > @@ -930,11 +931,18 @@ int cdc_ncm_bind_common(struct usbnet *dev,
> struct usb_interface *intf, u8 data_
> >  	usb_set_intfdata(ctx->control, dev);
> >
> >  	if (ctx->ether_desc) {
> > +		struct sockaddr sa;
> > +
> >  		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc-
> >iMACAddress);
> >  		if (temp) {
> >  			dev_dbg(&intf->dev, "failed to get mac address\n");
> >  			goto error2;
> >  		}
> > +		if (get_acpi_mac_passthru(&intf->dev, &sa) == 0) {
> > +			memcpy(dev->net->dev_addr, sa.sa_data, ETH_ALEN);
> > +			if (usbnet_set_ethernet_addr(dev) < 0)
> > +				usbnet_get_ethernet_addr(dev, ctx-
> >ether_desc->iMACAddress);
> > +		}
> >  		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net-
> >dev_addr);
> >  	}
> 
> So you want to run a Dell specific ACPI method every time anyone plugs some
> NCM class device into a host supporing ACPI?  That's going to annoy the hell out
> of 99.9997% of the x86, ia64 and arm64 users of this driver.
> 
> Call ACPI once when the driver loads, and only if running on an actual Dell
> system where this method is supported.  There must be some ACPI device ID you
> can match on to know if this method is supported or not?
> 
> 
> Bjørn

I have to agree - this is missing an identifying factor of the D6000.  It shouldn't be
running on "just any" cdc_ncm device.

The code that is in get_acpi_mac_passthrough checks for a properly built ACPI method
though.