Re: Migrating to larger numbers

Matt Aubury (Matt.Aubury@comlab.ox.ac.uk)
Tue, 8 Jun 1999 15:23:30 +0100


On Tue, Jun 08, 1999 at 03:46:50PM +0200, Jamie Lokier wrote:
> Matt Aubury wrote:
> > -- Do dynamic major allocation in the usual way.
>
> Can you do reliable dynamic major allocation?
> I didn't see any majors reserved for this.

Sadly it appears that there aren't (although I got a different
impression from Rubini's book). The major numbers are allocated
backwards from (MAX_CHRDEV-1).

> The major you pick might be one that is statically allocated by
> a device to be loaded later.

Possibly, but in that case it shouldn't be my driver at fault: the
allocations are done from a range marked "LOCAL/EXPERIMENTAL" in
devices.txt. Unfortunately, as it stands the dynamic allocation code
has major 0 as its lower bound :-/

A sensible policy, IMHO, would be to mark this upper range as
dedicated to dynamic allocation. It's only a documentation issue then.

Cheers,
Matt

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