From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH 2/9] drm/i915: [sparse] don't use variable
 size arrays
Date: Wed, 18 Apr 2012 11:05:29 +0200
Message-ID: <20120418090529.GG5315@phenom.ffwll.local>
References: <1334610468-9274-1-git-send-email-ben@bwidawsk.net>
	<1334610468-9274-3-git-send-email-ben@bwidawsk.net>
	<CA+gsUGS+yy6DbqhrtDt==XWzQdB6z0vkiE-b8qPqmSx7C6ObNw@mail.gmail.com>
	<20120417192035.5b3e58a4@bwidawsk.net>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org>
Received: from mail-ey0-f177.google.com (mail-ey0-f177.google.com
	[209.85.215.177])
	by gabe.freedesktop.org (Postfix) with ESMTP id D2074A0A72
	for <intel-gfx@lists.freedesktop.org>;
	Wed, 18 Apr 2012 02:04:31 -0700 (PDT)
Received: by eaak13 with SMTP id k13so1828116eaa.36
	for <intel-gfx@lists.freedesktop.org>;
	Wed, 18 Apr 2012 02:04:31 -0700 (PDT)
Content-Disposition: inline
In-Reply-To: <20120417192035.5b3e58a4@bwidawsk.net>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=subscribe>
Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org
Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org
To: Ben Widawsky <ben@bwidawsk.net>
Cc: intel-gfx@lists.freedesktop.org, Ben Widawsky <benjamin.widawsky@intel.com>
List-Id: intel-gfx@lists.freedesktop.org

On Tue, Apr 17, 2012 at 07:20:35PM -0700, Ben Widawsky wrote:
> On Tue, 17 Apr 2012 22:39:15 -0300
> Paulo Zanoni <przanoni@gmail.com> wrote:
> 
> > 2012/4/16 Ben Widawsky <ben@bwidawsk.net>:
> > > Sparse doesn't like:
> > > "error: bad constant expression"
> > >
> > 
> > <bikeshedding>
> > I know you'll hate me for asking, but: how difficult is it to fix sparse?
> > Adding those mallocs/frees increases the code complexity, making it
> > harder to read...
> > </bikeshedding>
> > 
> 
> I don't consider this a bikeshed. I've always been "under the
> impression" C99 was sort of taboo in the kernel. In this case
> specifically, it's never a great idea to allocate an unknown amount of
> stack space as it probably messes with some of the static tools and
> such.
> 
> In other words, I believe the right thing to do here is not to fix
> sparse. Plus there is precedent in other drivers to fix this kind of
> thing for sparse. I originally had this patch create an arbitrarily
> large object on the stack and fail if the args_len was too big. I can
> go back to that certainly if people prefer.

I've picked up the first 2 patches of this series for -next, with a tiny
bikeshed on the 2nd one. I've gotten stuck while reviewing the next one,
I think it'd be good if we can quickly discuss these on irc.
-Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48