lkml.org 
[lkml]   [2006]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRE: Can Linux live without DMA zone?
Date
From
Most PCs do not have ISA or floppy, so maybe we could add an option to enable DMA zone or not.

Best regards,
Conke @ AMD, Inc.

-----Original Message-----
From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Arjan van de Ven
Sent: 2006年11月2日 17:16
To: Jun Sun
Cc: linux-kernel@vger.kernel.org
Subject: Re: Can Linux live without DMA zone?

On Wed, 2006-11-01 at 18:15 -0800, Jun Sun wrote:
> I am trying to reserve a block of memory (>16MB) starting from 0 and hide it
> from kernel. A consequence is that DMA zone now has size 0. That causes
> many drivers to grief (OOMs).
>
> I see two ways out:
>
> 1. Modify individual drivers and convince them not to alloc with GFP_DMA.
> I have been trying to do this but do not seem to see an end of it. :)
>
> 2. Simply lie and increase MAX_DMA_ADDRESS to really big (like 1GB) so that
> the whole memory region belongs to DMA zone.
>
> #2 sounds pretty hackish. I am sure something bad will happen
> sooner or later (like what?). But so far it appears to be working fine.
>
> The fundamental question is: Has anybody tried to run Linux without 0 sized
> DMA zone before? Am I doing something that nobody has done before (which is
> something really hard to believe these days with Linux :P)?

on a PC there are still devices that need memory in the lower 16Mb.....
(like floppy)

Maybe you should reserve another area of memory instead!


--
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-11-02 11:37    [W:0.048 / U:0.232 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site