Re: [PATCH v2 2/2] irqchip: al-fic: Introduce Amazon's Annapurna Labs Fabric Interrupt Controller Driver

[Benjamin Herrenschmidt]

On Wed, 2019-06-05 at 16:12 +0100, Marc Zyngier wrote:
> > Those error messages are control path messages. if we return the same 
> > error value from here and from the previous error, how can we 
> > differentiate between the two error cases by looking at the log?
> > 
> > Having informative printouts seems like a good idea for bad 
> > configuration cases as such, wouldn't you agree?
> 
> I completely disagree. The kernel log isn't a dumping ground for this
> kind of pretty useless information. Furthermore, the irq subsystem will
> also shout at you when it gets an error, so no need to add insult to injury.
> 
> If you really want to keep them around, turn them into pr_debug.

I disagree Marc. This is a rather bad error which indicates that the device-tree
is probably incorrect (or the HW was wired in a way that cannot work).

Basically a given FIC can either be entirely level sensitive or entirely edge
sensitive. This catches cases where the DT has routed a mixed of both to the
same FIC. Definitely worth barfing loudly about rather than trying to understand
subtle odd misbehaviours of the device in the field.

Cheers,
Ben.