Fresh from reading linux/Documentation/IO-mapping.txt (written by
Linus), I have a couple dumb questions that hopefully someone will
answer:
IO-mapping.txt describes reading from I/O space like
unsigned value = readl(0xc0000);
but it describes writing with ioremap().
Why does reading not require ioremap, while writing does?
And the file seems to imply that read/write[bwl] should be the sole way
to address I/O memory.
Why, then, does drivers/video/matroxfb.c have code for the case where
READx_WORKS is not true? Is this simply a performance optimization, or
a real requirement?
Thanks,
Jeff
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