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    SubjectRe: Fwd: Patch to control VGA bus routing and active VGA device.
    On Fri, Jan 28, 2005 at 12:33:20PM -0700, Grant Grundler wrote:
    > > > If it is intended to work with multiple IO Port address spaces,
    > > > then it needs to use the pci_dev->resource[] and mangle that appropriately.
    > >
    > > There is no resource for some of the I/O port space that cards respond to.
    >
    > Yes - I've heard several graphics cards are horrible broken WRT address
    > decoding. Are PCI quirks supposed to handle that sort of thing?

    No, PCI quirks are for fixing broken things. VGA cards are entitled to
    3c0-3df and all their 10-bit aliases. I've been thinking for a while that we should mark the 10-bit aliases of ISA devices as used ... ie:

    x100-x3ff
    x500-x7ff
    x900-xbff
    xd00-xfff

    Unfortunately, that may break some legitimate setups, but is hinted at
    being a good idea in the EISA docs I've read. My laptop uses only the
    10-bit aliases of motherboard space (x000-x0ff, x400-x4ff, x800-x8ff,
    xc00-xcff) for devices, except for the ISA bridge, which gets:
    1180-11bf : 0000:00:1f.0
    1180-11bf : pnp 00:0b

    The K6-2 is similar; only 10-bit aliases of motherboard space except for:
    0a79-0a79 : isapnp write

    Possibly a better solution (less likely to break things) would be to allow
    drivers to reserve the 10-bit aliases too. Something like this:

    static inline void request_isa_alias_regions(unsigned long start,
    unsigned long n, const char *name)
    {
    int base;
    for (base = 0x400; base < 0x10000; base += 0x400) {
    request_region(base + start, n, name);
    }
    }

    and then call that in drivers/video/console/vgacon.c

    Russell, would that allay your issues with the kernel io resource database?

    --
    "Next the statesmen will invent cheap lies, putting the blame upon
    the nation that is attacked, and every man will be glad of those
    conscience-soothing falsities, and will diligently study them, and refuse
    to examine any refutations of them; and thus he will by and by convince
    himself that the war is just, and will thank God for the better sleep
    he enjoys after this process of grotesque self-deception." -- Mark Twain
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