svn commit: r186182 - head/sys/dev/ata

[M. Warner Losh]

In message: <20081228053530.GF18389 at elvis.mu.org>
            Alfred Perlstein <alfred at freebsd.org> writes:
: * Scott Long <scottl at samsco.org> [081226 18:34] wrote:
: > 
: > On Dec 26, 2008, at 5:38 PM, Alfred Perlstein <alfred at freebsd.org>  
: > wrote:
: > >
: > >Easy enough to stash a "once" varible in the generic device struct
: > >and warn when returning from an isr when INVARIANTS or something is
: > >turned on.
: > >
: > >Then you'd only get one warning per device once it happens.
: > >
: > >
: > 
: > I prefer to do nothing.  It's not unsafe or erroneous to access cfg  
: > registers.  But if some kind of message does get added, I insist that  
: > it drop all pretenses and say, "you're too poor to run freebsd, come  
: > back when you can afford better hardware.". :)
: 
: Well that could be the result of a driver that has a "bug" that
: makes it access cfg space when it does not need to, as what seems
: to have just been fixed.

I think we need to have better tools to peer into what's going on
inside a driver (or other well defined areas of the kernel).  Maybe
dtrace might be the right way to do this?

Warner