BIOS behavior on BIOS and memory space enable bit

[wen-king@myri.com (Wen-King Su)]

During a logic analyzer test of my pci board, I caught the BIOS fiddling
with the memory space enable bit before it set the memory BAR.  Apparently
it is trying to use the writability of the memory space enable bit to
determine whether the board contain memory space BARS.  Is this something
that is OK for BIOS to do?   It appears to be quite dangerous as it would
turn on the board's address decoding mechanism without knowing if doing
so will create address conflicts.  What fun if you happens to have two
memory BARs on the same board and both of them are mapped to zero. 
½
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