From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030333AbWJKLYp (ORCPT ); Wed, 11 Oct 2006 07:24:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030331AbWJKLYo (ORCPT ); Wed, 11 Oct 2006 07:24:44 -0400 Received: from cantor2.suse.de ([195.135.220.15]:20608 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1030333AbWJKLYn (ORCPT ); Wed, 11 Oct 2006 07:24:43 -0400 Date: Wed, 11 Oct 2006 13:24:36 +0200 From: Nick Piggin To: Thomas Hellstrom Cc: Linux Kernel Subject: Re: [patch 4/5] mm: add vm_insert_pfn helpler Message-ID: <20061011112436.GA6835@wotan.suse.de> References: <20061010121314.19693.75503.sendpatchset@linux.site> <20061010121357.19693.7339.sendpatchset@linux.site> <452CC383.4050401@tungstengraphics.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <452CC383.4050401@tungstengraphics.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 11, 2006 at 12:12:19PM +0200, Thomas Hellstrom wrote: > Nick, I just realized: would it be possible to have a pgprot_t argument > to this one, instead of it using vma->vm_pgprot? > > The motivation for this (DRM again) is that some architectures (powerpc) > cannot map the AGP aperture through IO space, but needs to remap the > page from memory with a nocache attribute set. Others need special > pgprot settings for write-combined mappings. > > Now, there's a possibility to change vma->vm_pgprot during the first > ->fault(), but again, we only have the mmap_sem in read mode. I don't see a problem with that. It would be nice if vm_pgprot could be kept in synch with the pte protections, but I guess a crazy driver should be allowed to do anything it wants ;)