Date: Fri, 17 Mar 1995 12:27:49 -0800 From: "Justin T. Gibbs" <gibbs@estienne.CS.Berkeley.EDU> To: se@MI.Uni-Koeln.DE (Stefan Esser) Cc: current@FreeBSD.org Subject: Re: Sharing interrupts with PCI devices? Message-ID: <199503172027.MAA16591@estienne.cs.berkeley.edu> In-Reply-To: Your message of "Fri, 17 Mar 1995 10:54:34 %2B0100." <199503170954.AA26274@FileServ2.MI.Uni-Koeln.DE>
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>On Mar 16, 18:49, "Justin T. Gibbs" wrote: >} Subject: Sharing interrupts with PCI devices? >} I saw some commits go by about sharing interrupts under PCI. The >} PCI motherboard I have has an aic7870 on it, and when a 2940 is >} also in the machine, the bios assigns them the same interrupt. >} The probe appears to run fine for the first card, but the second >} card hangs sortly after initialization. I haven't found a way to >} force them onto separate interrupts in the BIOS or elsewhere, so >} it looks like I'm stuck (the onboard controller cannot be disabled >} :-(). Does the PCI code already contain logic to pass the proper >} unit number down to the driver if two cards use the same interrupt? > >Shared interrupts have been working >for some time on our local systems, >and the code will be put into the >CVS repository Real Soon Now (TM). > >PCI interrupts can be shared, but ISA >interrupts will have to be assigned >uniquely as before. > Why can't we chain them? I thought that the PCI spec allowed for PCI devices to share ISA irqs. > >The PCI code generally finds the IRQ >line the PCI interrupt is routed to >by a PCI BIOS call, or (as the current >BSD code does) in a PCI configuration >space register. I take it that both methods return the same result. >The NCR driver doesn't install an >interrupt handler if the IRQ found >this way is '0'. It works in a polled >mode instead. There is nothing to >prevent you from making the driver >configuration depend on the IRQ being >specified. So it's in fact quite easy >to selectively disable the aic7870 in >the above mentioned case ... So how do I enforce an irq? Can I just specify it in the kernel config file? My irq comes out as 10 for both the onboard controller and the separate 294x. > > >Regards, STefan > >-- > Stefan Esser Internet: <se@ZPR.Uni-Koeln.DE> > Zentrum fuer Paralleles Rechnen Tel: +49 221 4706019 > Universitaet zu Koeln FAX: +49 221 4705160 > Weyertal 80 > 50931 Koeln -- Justin T. Gibbs ============================================== TCS Instructional Group - Programmer/Analyst 1 Cory | Po | Danube | Volga | Parker | Torus ==============================================
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