generic bridge support was biting us more than it helped, whenever a new chipset
came out from a vendor and misprogramming it caused strange hangs or corruption.
[2] Add a large number of PCI IDs based on what the linux drivers support.
Note that the new PCI IDs haven't been tested, they're just *likely* to work.
In particular the VIA AGP 8x chipsets are concerning, due to lack of testing,
possible issues (kern/69953), and not having a nice "does this bridge say it
would do 8x" function. However, this shouldn't make the situation worse, since
these chips would have probed in the past anyway.
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