Re: RFC: Platform data for onboard USB assets

[Nicolas Pitre]

On Fri, 11 Mar 2011, Greg KH wrote:

> On Fri, Mar 11, 2011 at 05:08:07PM +0000, Mark Brown wrote:
> > On Fri, Mar 11, 2011 at 08:56:42AM -0800, Greg KH wrote:
> > > On Fri, Mar 11, 2011 at 04:48:50PM +0000, Mark Brown wrote:
> > 
> > > > USB itself is discoverable but the when the USB bus you're looking at is
> > > > one that's soldered down onto a board in a specific design all bets are
> > > > off regarding how complete the information you get will be.  On a basic
> > > > level the designers may have done things like omit the configuration
> > > > EEPROMs that would set the device IDs that the driver should be relying
> > > > on to identify the hardware configuration.  There may be other, nastier,
> > > > things going on.
> > 
> > > Then you use the existing platform data for your USB host controller
> > > driver.  Doesn't that work today just fine?
> > 
> > Wrong end of the bus.  This stuff is simple enough to deal with in a
> > system specific fashion, the standard solution would be to patch the
> > relevant drivers to hard code whatever is required.
> 
> What drivers need this?  Specifics please.

Let me quote Arnd Bergmann:

|I have just verified with my Pandaboard that the pins on the SMSC9514
|usb ethernet that are meant to be connected to a serial EEPROM are
|indeed not connected anywhere.

> I would brand these types of systems "extremely broken" :)

Indeed.  But to hardware people, modifying the software is always cheaper.

> Anyway, specifics are the best way forward if anyone has such a messed
> up system.

PandaBoards are becoming quite popular.


Nicolas
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