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    SubjectRe: Removal of pci_find_* in 2.5
    Alan Cox wrote:
    > On Sat, 2002-07-13 at 05:41, Jeff Garzik wrote:
    >
    >>ordering, is simply hard-coding something that should really be in
    >>userspace. Depending on pci_find_device logic / link order to
    >>still-boot-the-system after adding new hardware sounds like an
    >>incredibly fragile hope, not a reliable system users can trust.
    >
    >
    > For hot plugging obvious. At system boot time however the ordering and
    > seeing the ordering is rather important because in many cases the
    > ordering is what tells you about things like IDE controller pairing. It
    > tells you what order to assign many scsi devices because the ordering is
    > defined by their BIOS ROM.
    >
    > One way to handle this generically would be to use pci_register_device,
    > but in the register function for such wacky devices during boot up we
    > merely keep track of what we have to look into.


    My point is that depending on any method of internal kernel ordering is
    fragile.

    I would rather have the kernel export which drives are listed in CMOS /
    BIOS ROM, and let userspace say "my boot drive is the nth BIOS-listed
    drive." For example, looking through the aic7xxx (or was it
    ncr53c8xxx?) drive, it gets boot drive ordering from BIOS/CMOS. That
    piece of info can either be exported by driverfs from the low-level SCSI
    driver, or by a separate, tiny ncr53c8xxx_boot_drive driver.

    Depending on pci_find_* ordering is very situation-dependent, and only
    covers N cases. Then you have another N cases covered by the order in
    which you modprobe key drivers. Then you have another N cases covered
    by special case code somewhere. You'll never get all these cases right,
    in the kernel, the way the user wants. That's why I say the
    responsibility for figuring out the boot drive should be pushed to
    initrd/initramfs.

    Jeff


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