Re: [PATCH] au1x00 serial real interrupt

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Russell King wrote:

>>   Well, after looking at drivers/serial/8250.c a bit more, I think this 
>>   may be even more simlified since that driver seems to treat the negative 
>>values as completely invalid anyway. IOW, we can just:

>>#define is_real_interrupt(irq)	1

>>   Russel, what do you think?

> That's Russell 8)

    I'm sorry. :-)

> Well, if you need IRQ0 to be real then redefining is_real_interrupt()
> is the correct way forward.

> However, Linus' policy is that IRQ0 shall be invalid at least on PCI
> systems, and architectures _should_ remap their real IRQ0 to some other
> number.

   Hm, given that NO_IRQ is #defined as -1 (when it's defined at all)...

>  Personally I don't like this.

    Hm, me neither but I can undestand the reasoning. 0 is the usual default
value of the PCI interrupt line register, meaning interrupt is unassigned.

 > Hence why I prefer to give people the option.

    Thanks for the explanation.
    Would be better probably to have that #define in 8250.c going after 
#include <asm/serial.h> but as this seems the first and only case of the 
override needed, it's good enough this way. :-)
    As for the PCI UARTs possibly plugged into Alchemy board, I really don't 
know... This macro has no provision to check for the UART type. So, skipping 
its invocation in 8250.c for UPIO_AU case might be a better (though not 
cleaner) solution...

WBR, Sergei