Re: AHCI driver preferring nr_ports over port map

[Tejun Heo <htejun@gmail.com>]

Jan Beulich wrote:
>> Do you have any real case where the above behavior causes problem?
> 
> It's not strictly a problem (i.e. nothing really mis-behaves), but it made
> me wonder why the box I saw this on gets 6 ahci device instances set
> up when spec as well as port map say there ought to be only 5. After
> looking at the ESB2 spec it seemed that behavior was clearly violating
> the spec: "For ports that are not available, software must not read or
> write to registers within that port.", which contradicts status being
> displayed for (and therefore status being read) from the 6th (not
> present) port.

Well, two values don't agree with each other and we know for a fact that
vendors sometimes get PI wrong, so we trust n_ports in such cases.  We
can reverse the behavior but that's likely to cause more problems than
it fixes.

-- 
tejun