8250.c::autoconfig() fails loopback test on MPC824[15]

[Segher Boessenkool]

> Maybe the best solution would be for 824[15] to not claim compatibility
> with 8250 at all then.

Or at least it should have a more specific entry for this
"special" 16x50 UART, and that one should be probed first.

> If the device tree contains an entry that matches
> what the generic driver looks for, it better be something that can
> be handled by that driver.

Pretty much; you can't make this rule too strict though,
if a device mostly works with the generic driver, you can
claim compatibility with it -- keep in mind that that can
come back to bite you though, like in this case.  The
advantages do outweigh the disadvantages sometimes, it's
all a tradeoff; avoid it if possible.


Segher