[PATCH] Re: Linkstation Mini and __machine_arch_type problem, not booting since 3.8

[Benjamin Cama]

Le vendredi 19 juin 2015 à 16:44 +0100, Russell King - ARM Linux a
écrit :
> On Fri, Jun 19, 2015 at 03:46:45PM +0200, Benjamin Cama wrote:
> > Hi Russell,
> > Do not misunderstand me: I am not at all for keeping the situation like
> > this! What I ask is just for users to be notified of this new requirement:
> > for my case, my board simply couldn't boot anymore, without any
> > explanation.
> 
> It's not a new requirement.  It's something that's been there all along,
> and is finally starting to bite places where it never used to bite before.
> It's a latent bug in platform code, that's all.
> 
> This "IRQ0 is bad" has been known for quite some while - you've already
> been pointed at Linus' rant about it, dated 25 Jan 2007.  If you do a bit
> of research, you'll find that the orion code was contributed _after_ that
> date.

Yes, I understand.

> While it's easy to stick a warning into orion_irq_init() (or whatever the
> function is called), it's utterly pointless now that it's been found -
> just fix all the users of orion_irq_init() now and be done with it.

Well, I could do that but I do not have all the hardware to test it on.

> As for "shouldn't this have had a warning in the past", well, maybe, but
> consider this task:
> 
> 	> Please go and look at the other mach-* directories, and find
> 	> all those which might use IRQ0, and arrange for them to print
> 	> a warning.
> 
> I'm sure you'll see what a task it is that you're asking for.
> 
> What you're asking for is actually unreasonable.

I was not at all asking for that, sorry for the misunderstanding again:
I was imagining putting a warning or BUG_ON in e.g.
irq_alloc_generic_chip (and just one place; I am not even sure this is
the right one: I am quite a beginner in kernel code, to put things in
context). I tried that but with bad results (just a hard reboot for
BUG_ON without message) maybe because without earlyprintk, it happens
too early in the boot process to display anything to the user. So this
is a bad idea indeed.

> (I am aware that Dove broke exactly for this reason, and I've been
> carrying a patch since December 2014 to fix Dove - but I just don't have
> the time to get it merged - like most of my other Dove work.)

I tried a quick grep'ing of platforms allocating IRQ0, and all Orion is
indeed doing it, as well as davinci. But apart from them, the rest
seems OK, so the platforms having this problem seem indeed to be very
few.

Regards,
--
benjamin