Re: RFC: Platform data for onboard USB assets

From: Greg KH
Date: Thu Mar 17 2011 - 17:33:10 EST

On Thu, Mar 17, 2011 at 09:24:49PM +0000, Mark Brown wrote:
> On Thu, Mar 17, 2011 at 01:26:14PM -0700, Greg KH wrote:
> > On Thu, Mar 17, 2011 at 08:18:35PM +0000, Mark Brown wrote:
> > > It's going to be an off the shelf USB ethernet controller. I'd be
> > > astonished if the board-configurable device IDs weren't set from the
> > > same SEPROM that the MAC address is so it'd just show up as a generic
> > > chip of whatever kind.
> > Huh? All USB controllers you buy have the ability to set the vendor and
> > product id, so you should always be able to key off of that.
> > Isn't that the case here?
> They generally the same facility that includes the ability to set the
> MAC address so if one's not been provided it seems optimistic to expect
> the other.

{sigh} You are probably right :(

> The way this is normally done is that the ethernet controller can be
> attached to a SEPROM which it reads when it powers on. This will
> contain a number of device configuration parameters, including the
> vendor IDs and the MAC address, which will be configured before the
> device makes itself available on the bus. If the system integrator has
> omitted the SEPROM then the device will come up with defaults, usually
> something like all zeros.

Ok, then again, let's deal with this on a case-by-case basis please, as
this is going to be a "rare" thing in the real world. I don't want to
encourage _any_ engineers to think that this is ok to do for USB

Patches to fix this, for this specific PandaBoard controller are gladly
accepted. What's odd is this is explicitly a Linux development board,
so you would think that this could have been caught, and fixed, in the
hardware a long time ago, right?

Heck, it could be fixed today on future versions of this board, if
anyone from TI actually cared :(


greg k-h
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