Date: Sat, 10 Feb 1996 03:34:58 +0100 From: se@zpr.uni-koeln.de (Stefan Esser) To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: hackers@freebsd.org Subject: Re: scanpci.c and pci-related stuff Message-ID: <199602100234.AA22397@Sysiphos> In-Reply-To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> "Re: scanpci.c and pci-related stuff" (Feb 9, 16:30)
next in thread | previous in thread | raw e-mail | index | archive | help
On Feb 9, 16:30, Luigi Rizzo wrote:
} Subject: Re: scanpci.c and pci-related stuff
} > You can change this value without knowing
}
} I guess you mean "cannot"
Yes. I really shouldn't write mail replies long
after midnight after working some 16 hours (what's
the current time :)
} > the details of the chip set. There are now
} > PCI BIOS calls that ought to allow such an
}
} From the meteor.c driver :
}
} ...
} #ifdef METEOR_IRQ /* from the meteor.h file */
} old_irq = pci_conf_read(tag, PCI_INTERRUPT_REG);
} pci_conf_write(tag, PCI_INTERRUPT_REG, METEOR_IRQ);
} new_irq = pci_conf_read(tag, PCI_INTERRUPT_REG);
} printf("meteor_attach: irq changed from %d to %d\n", (old_irq & 0xff),
} (new_irq & 0xff));
} #endif METEOR_IRQ
} ...
}
} it looks like it is not that hard, if the above works.
Yes. It looks trivially simple.
And it does of course not work at all ...
The PCI_INTERRUPT_REG is a Byte register, which
has the sole purpose to let the driver know about
the BIOS provided interrupt routing setup.
You can change this value to whatever you want,
but all it will do is confuse whoever later reads
the register and believes what he finds :)
} Note that I don't want to chang IRQ settings for an active board, just
} to remap the setting for a board which is not correctly recognised.
} It is intended as a fixit tool, "use at your own risk".
It is a NOOP ...
(Well, not really. The code later uses this value
for the call to register_intr(). But the only reason
for a wrong number being written by the BIOS is, that
the IRQ routing is done in hardware (i.e. by jumpers)
and the PCI BIOS settings have not been adjusted
accordingly. Such BIOS jumpers were state of the art
in mid 1994, but I doubt there are many systems that
still use them. And the correct values have just to
be entered in teh BIOS setup ...)
} I have two identical PC-net PCI boards, plugged in adjacent slots.
} On one particular motherboard they are both configured with IRQ10, on a
} similar motherboard one gets IRQ10, the other IRQ11
Yes, I just read your other message ...
The problem is the level of PCI support for the Lance.
It needs just a few hours of work, I guess ...
} Also, at times I'd like to free some specific IRQs. As an example: here
} I have a system with the following devices:
}
} sio0,1,2 (irq 3, 4, 5)
} lpt0 (irq7)
} ed0 (irq10, PCI)
} meteor (irq9,PCI)
} vga (irq11, PCI)
}
} and I'd like to put in a scanner (can use irq3,5,10) and an SB16.
} I must free irq10, and possibly irq9 as well.
I don't know how your PCI BIOS chooses the IRQ values.
All PCI cards but the Lance Etherner cards can share
an interrupt. I prefer boards, where I can assign any
IRQ to IntA of each PCI slot, but current systems are
delivered as PnP, and they just don't offer this config
mode anymore ...
You really need the PCI attach code for the Lance ...
Regards, STefan
--
Stefan Esser, Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021
Universitaet zu Koeln, Weyertal 80, 50931 Koeln FAX: +49 221 4705160
==============================================================================
http://www.zpr.uni-koeln.de/~se <se@ZPR.Uni-Koeln.DE>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199602100234.AA22397>