Messages in this thread | | | Date | Wed, 24 Nov 1999 12:49:30 -0500 | From | Wakko Warner <> | Subject | Re: Hot PCI bus plugging |
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> > Looks like noone brought up the subject of resource allocation, so I will. > > I don't know much about the bios and PCI as far as this goes, but doesn't > > the bios assign io/mem/irq at boot up? How would this work on hot plug pci? > > Who or what assigns the resources? > > Yes you have a very good point there, that I mentioned in a private > e-mail. The BIOS does that at bootup, so we would have to assume > control of that ourselves. That wouldn't be too difficult, but would > add some housekeeping to the PCI layers -- mainly allocating and keeping > track of IRQs and base addresses/ranges. We also have to be careful > to make sure we don't share IRQs with devices that don't want to share > them -- introducing the possibility the user could insert a card that > can't get an IRQ (ouch) because there are none available. (Dang those > broken cards that don't share.. Why doesn't everybody just read the > friggin' PCI spec??? :) )
Also speaking of that, what about systems that actually put pci devices on irq 16+? I've seen some (NT hated it, linux didn't care <eg> It was a supermicro dual ppro) board do it like the one I just meantioned. I believe some tyan boards (like the one I have, but mine doesn't allocate higher than 15) do it as well.
I wasn't aware that some pci devices don't like sharing IRQs. I didn't think it mattered.
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