Re: PageReserved removal woes: vbetool, suspend-to-ram breakage

From: Matthew Garrett
Date: Tue Nov 22 2005 - 13:55:44 EST


Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> wrote:

> Just wanted to let you know that the warning introduced in
> [PATCH] core remove PageReserved

It's not much of a warning, it seems to stop vbetool from working (which
may explain a few complaints about ACPI suspend being broken in 2.6.15 -
it's not, but vbetool is...)

vbetool (well, strictly it's LRMI, but...) needs to access real-mode
memory. On the other hand, it's probably a bad idea to let it actually
scribble over RAM that the kernel may be using. So
MAP_PRIVATE|PROT_WRITE seems to be the correct thing to do. This
certainly /seemed/ to work in older kernels, but doesn't any more. What
should I be doing instead?

(I'm also not quite sure why the error claims that it's deprecated,
whereas in fact it doesn't actually work at all. Breaking userspace
without warning isn't terribly nice)
--
Matthew Garrett | mjg59-chiark.mail.linux-rutgers.kernel@xxxxxxxxxxxxx
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