[Asterisk-Users] PCI front mount chassis?

[Anton Tinchev]

Steven Critchfield wrote:

>On Fri, 2004-03-12 at 05:26, Rich Adamson wrote:
>  
>
>>>>I too am running 6 cards in my system, although not in a "high traffic 
>>>>capacity" load environment.
>>>>
>>>>So far my (limited) high-load simulations have shown no problems.
>>>>        
>>>>
>>>So - is it apocryphal that the Digium cards (drivers) won't share
>>>interrupts?
>>>
>>>If there is a real issue with sharing interrupts then it seems to me
>>>to be a bug that needs fixing.  PCI bus supports shared interrupts,
>>>why doesn't the hardware/driver?
>>>      
>>>
>>In most cases, sharing an interrupt is not a problem at all. There have
>>been a few cases where _some_ issue was resolved by moving cards around,
>>however the majority of those seem to be: a) abrupt system changes with
>>no effort to seriously identify the root-cause, b) newbie installations
>>where the condition of the underlying system infrastructure is totally
>>unknown, or, c) wild recommendations that might have had some basis a
>>long time ago but no longer apply.
>>    
>>
>
>What I was referring to in this case about sharing an IRQ was the actual
>wire trace in the PCI bus. As I understand the PCI spec, there are 4
>interrupt lines called A,B,C, and D. In slot 1, They appear in that
>order. In slot 2 they shift, in slot 3 they shift and again in slot 4.
>By the time you get to slot 5, all interrupts have been in each of the 4
>spots and now they have the choice of staying in the same as slot 4 or
>shifting again. Most cards use interrupt line A as if they are in slot
>1, and therefore if you move them from one slot to another, they would
>most likely get their own access to the interrupt line.
>
>This is part of the reason why moving a card around in the chassis
>helps. This is also why I would be cautious of trying to run more than 4
>high interrupt cards on the PCI bus. 
>
>My next point would be that of, if you need more than 4 cards, you need
>more than 1 computer controlling it. That is way too many eggs for one
>basket. 
>  
>
Most of the 3.3V Boards have more then 1 pci bus. The boards that i use 
have 3 PCU Busses - 3xXPCI, 3xPCI66, Internal with Adaptec, ide and 
E1000 on board