From: Dumas Patrice (dumas@centre-cired.fr)
Date: Thu Sep 28 2000 - 20:55:07 CEST
Michele Andreoli a écrit :
>
> Thank much for the clarification. But, anycase, why my ethernet PCI
> do not requires *explicity* an ioport?
If I remember well, PCI devices can share an io addresses range, ie it is
allocated on the run by the bios (?). But I am not sure. For old ISA
cards, you have to change the io ranges with jumpers. Newer ones can be
plug and play, so you still have to specify the memory base address, but
without needing the jumpers.
It is the same for irq.
> A look in the /proc/ioports shows:
>
> ==========================================
> 0000-001f : dma1
...
>
> d808-d80f : ide1
> ==========================================
>
> so, it is now clear, ioports is the rule, not the exception,
> included keyboard.
> How to distinguish memory-space from io-space starting from
> this hex address?
There is a bit on the bus that is set to 1 if it is a io memory address,
and to 0 if it is a RAM address. So the devices only listen to the
appropriate memory type.
For the kernel point of view, I remember that there is a file in the
kernel doc explaining how the kernel sees those 2 kinds of memory, but I
only remember that I didn't understood much....
Pat
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