Date: Thu, 11 Dec 2008 17:35:48 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frans Pop <elendil@planet.nl>, Eric Anholt <eric@anholt.net>,
       nix.or.die@googlemail.com, linux-kernel@vger.kernel.org, rjw@sisk.pl,
       Arjan van de Ven <arjan@infradead.org>
Subject: Re: Linux 2.6.28-rc8
Message-ID: <20081211163548.GA11859@elte.hu>
References: <alpine.LFD.2.00.0812101651130.3340@localhost.localdomain> <49407CE1.9090600@googlemail.com> <49407CE1.9090600@googlemail.com> <1228979963.3254.8.camel@gaiman.anholt.net> <200812111707.20857.elendil@planet.nl> <alpine.LFD.2.00.0812110814360.3340@localhost.localdomain>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.LFD.2.00.0812110814360.3340@localhost.localdomain>
User-Agent: Mutt/1.5.18 (2008-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1995
Lines: 51


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> 
> 
> On Thu, 11 Dec 2008, Frans Pop wrote:
> 
> > Eric Anholt wrote:
> > > My recommended solution, of course, is to remove vesafb.
> > 
> > How is taking away useful functionality from users a better option than 
> > just fixing the bug?
> 
> Well, just to clarify: it's not a _bug_. It's a benign warnign that two 
> subsystems are trying to map the same memory differently.
> 
> In this case, we have:
> 
> 	resource map sanity check conflict: 0xd0000000 0xdfffffff 0xd0000000 0xd07effff vesafb
> 
> and what it means is that the caller (which is i915_gem_entervt_ioctl) is 
> trying to apparently ioremap the _whole_ graphics card MMIO resource 
> (0xd0000000-0xdfffffff), but the vesafb driver has already registered the 
> fact that it uses _part_ of that resource (0xd0000000-0xd07effff).
> 
> There's no bug there. It's a warning. It's usually a very odd situation 
> when somebody tries to ioremap something that crosses resource reservation 
> boundaries, but the thing is, in this case it's not really a problem.
> 
> It's triggered by a couple of oddities:
> 
>  - fbcon (vesafb) is odd and only requests a partial resource, because it 
>    only uses part of the MMIO window.
> 
>  - the interaction between fbcon and X is odd to begin with, since they 
>    both use the same physical resource.
> 
> so it's a generic warning that triggers because these things 
> _shouldn't_ happen, but it's not actually an error in this case. We 
> could just remove the warning. Or leave it in, in case it finds other 
> (real) issues, and just ignore it.

hm, the warning caught a couple of real bugs already. (one in some cpq 
driver, another was in some networking driver iirc)

	Ingo
--
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/