[ros-dev] APIC support on uniprocessor machines

Aleksey Bragin aleksey at studiocerebral.com
Tue May 24 11:48:11 CEST 2005

    Hi James,
Really cromwell uhci isn't supposed to correctly load now (though it does to 
some extent now, thanks to hpoussin's work on resources assignment).

But, in fact, despite both uhci and ohci dprint they are using interrupts, 
don't believe your eyes. They don't do it for real :-).
OHCI has a workaround, which uses another thread (needed anyway, even if 
real interrupt is used), and thus it's doing it like 'in polled mode'.
UHCI doesn't have any workarounds at all, it's really version I adapted from 
Linux 2.5 usb code. But it's still way better than to invent wheel from 

So, APIC would be a great thing, but right now (until I or someone else does 
an interrupt handler in uhci) it won't make uhci better or worse :-)

----- Original Message ----- 
From: "James Tabor" <jimtabor at adsl-64-217-116-74.dsl.hstntx.swbell.net>
To: "ReactOS Development List" <ros-dev at reactos.com>
Sent: Tuesday, May 24, 2005 7:41 AM
Subject: [ros-dev] APIC support on uniprocessor machines

> Hi All,
> This may not be related to a problem I'm having. I can not load cromwell
> uhci driver. Ne2000 does load but unable to ping anything out side the 
> box.
> Both share irq 0xb or 11. I noticed we have apic and ioapic in 'mp'. How 
> hard
> would it be to port them over to 'up' for supporting uniprocessor. I could
> try but the group mood ATM is fairly poor. Other words I would not like to
> piss off anyone.
> Using APIC would fix interrupt sharing problems and expand Ros to a higher
> OS level.
> Thanks,
> James
> ps I did disable hive loading for the ne2000 but since the board is still 
> in
> the box, I guess it's causing problems.
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