Re: ioremap_nocache problem?

From: Stephen C. Tweedie (sct@redhat.com)
Date: Thu Jan 25 2001 - 10:16:55 EST


Hi,

On Tue, Jan 23, 2001 at 10:53:51AM -0600, Timur Tabi wrote:
>
> My problem is that it's very easy to map memory with ioremap_nocache, but if
> you use iounmap() the un-map it, the entire system will crash. No one has been
> able to explain that one to me, either.

ioremap*() is only supposed to be used on IO regions or reserved
pages. If you haven't marked the pages as reserved, then iounmap will
do the wrong thing, so it's up to you to reserve the pages.

Cheers,
 Stephen
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