reserve= specifies ..... iomem or ioport?

From: Dag B (dagb@os.telia.no)
Date: Sat Sep 23 2000 - 22:11:36 EST


This may be obvious to a programmer, but...:

./Documentation/more kernel-parameters.txt :

        reserve= [KNL,BUGS] force the kernel to ignore some iomem
area.

http://cuip.uchicago.edu/doc/lilo-0.21/ :

 reserve=<base>,<size>,... reserves IO port regions. This can be used to
prevent device drivers from auto-probing addresses where other devices
are
located, which get confused by the probing.

'man bootparam' :
   `reserve=...'
This is used to protect I/O port regions from probes. The form of the
command is:

              reserve=iobase,extent[,iobase,extent]...

In some machines it may be necessary to prevent device drivers from
checking for devices (auto-probing) in a specific region. This may be
because of hardware that reacts badly to the probing, or hardware that
would be mistakenly identified, or merely hardware you don't want the
kernel to initialize.

The reserve boot-time argument specifies an I/O port region that
shouldn't be probed. A device driver will not probe a reserved region,
unless another boot argument explicitly specifies that it do so.

For example, the boot line

              reserve=0x300,32 blah=0x300

keeps all device drivers except the driver for `blah' from probing
0x300-0x31f.

The more recent Linux documentation says iomem, while the majority of
other documentation says io port. Given that /proc/ contains both, I'd
like to see a clearification...

Dag B
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