Casper.Dik at Sun.COM wrote:
>> I see this in my messages since I put in the Wistron CM9 card that IRQ21 is 
>> shared between them.  
>>     
> Is there a way to change this to keep them on different IRQs? I didn't see 
> anything apparent in the
>  BIOS.  I've noticed my wireless isn't that fast nor seems very stable.
>
> There really should not be an issue with sharing IRQs.
>
> Casper
> _______________________________________________
> laptop-discuss mailing list
> laptop-discuss at opensolaris.org
>   

That really depends on the hardware and the device drivers.  I've seen
poorly written device drivers that don't share IRQs well (any driver
that either assumes that an interrupt means it should do work without
checking the device, or any driver that blindly returns DDI_INTR_CLAIMED
all the time), or drivers that do a lot of work in their handler
(assuming, perhaps incorrectly if shared with a different device, that
interrupts are not too performance critical), drivers sharing that have
different prioritization criteria (e.g. sharing with a serial port that
wants a high priority interrupt and an 802.11b device that maybe wants a
much lower priority), and even hardware that doesn't share well (e.g.
fifoless UARTs that _really_ need timely handling to avoid dropping
receive bytes).

It really is a good idea in my experience to minimize devices coexisting
on different IRQs, and then I try to put devices of the same type (e.g.
network cards with network cards, HBAs with HBAs, etc.) when sharing IRQs.

-- 
Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
http://www.tadpolecomputer.com/
Phone: 951 325-2134  Fax: 951 325-2191


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