Messages in this thread |  | | Date | Mon, 6 Jan 2003 13:52:10 -0800 | Subject | Re: [patch 2.5] PCI: allow alternative methods for probing the BARs | From | (Grant Grundler) |
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On Mon, Jan 06, 2003 at 06:33:28PM +0300, Ivan Kokshaysky wrote: > For now I'd start with following: > phase #1. pci_do_scan_bus() - build the bus/device tree, read in > dev/vendor IDs, header type and class code; call > "PCI_FIXUP_EARLY" fixups.
you meant pci_scan_bus() for #1?
(pci_do_scan_bus() is the implementation, but I thought arch code is supposed to call pci_scan_bus().)
> phase #2. pci_probe_resources(bus) - walk the bus tree again, > probe the BARs, maybe call pci_read_bridge_bases for > bridges; fill in the rest of PCI header; call "PCI_FIXUP_HEADER" > fixups. > (Also there are phases #3 and #4 - assign resources and assign unassigned > resources, but it's another story) ... > Hmm, this looks good - now we can do early bus-specific fixups > without introducing "pcibios_init_bus" thing (suggested by Grant and > myself quite a while ago).
I agree - it looks better. But I fail to see how it fixes the problem of knowing when we can or cannot disable a device in order to size the BAR. I'm under the impression some i386 specific code needs to be added to identify/fixup the broken configurations (memory disabled when a PCI Bridge is disabled).
I'm thinking the same logic needed by PCI hotplug to allow safe removal of a bridge device would be useful to determine if a PCI Bridge could be safely (temporarily) disabled (I'm thinking 4-port 100BT card). Ie a "no subordinate drivers active" and "not in use" checking.
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