Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753283Ab0DKXzo (ORCPT ); Sun, 11 Apr 2010 19:55:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39684 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753129Ab0DKXzm (ORCPT ); Sun, 11 Apr 2010 19:55:42 -0400 Subject: Re: [PATCH 1/3] fbmem: fix aperture overlapping check From: Dave Airlie To: marcin.slusarz@gmail.com Cc: LKML , dri-devel , nouveau@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Peter Jones , Andrew Morton In-Reply-To: <1270929334-3742-1-git-send-email-marcin.slusarz@gmail.com> References: <1270929334-3742-1-git-send-email-marcin.slusarz@gmail.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 12 Apr 2010 09:54:28 +1000 Message-ID: <1271030068.3554.1.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2652 Lines: 74 On Sat, 2010-04-10 at 21:55 +0200, marcin.slusarz@gmail.com wrote: > fb_do_apertures_overlap is returning wrong value when one aperture > is completely whithin the other. Add generic ranges_overlap macro > (probably kernel.h candidate) and use it here. > That doesn't seem right. The rules are: the generic aperture has to be equal or smaller than the hw aperture, otherwise the generic driver will be trashing random hw pieces on the machine. So with that in mind, the check makes sure the generic aperture starts somewhere inside the hw aperture, which the test clearly gets right. Have you got a pointer to a machine where it fails? Dave. > Signed-off-by: Marcin Slusarz > Cc: Dave Airlie > Cc: Peter Jones > Cc: Andrew Morton > --- > drivers/video/fbmem.c | 24 +++++++++++++++++------- > 1 files changed, 17 insertions(+), 7 deletions(-) > > diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c > index a15b44e..41f2e5e 100644 > --- a/drivers/video/fbmem.c > +++ b/drivers/video/fbmem.c > @@ -1468,15 +1468,25 @@ static int fb_check_foreignness(struct fb_info *fi) > return 0; > } > > +/** > + * ranges_overlap - check whether two ranges overlap (their intersection is not empty) > + * @start1: start of the first range > + * @size1: length of the first range > + * @start2: start of the second range > + * @size2: length of the second range > + */ > +#define ranges_overlap(start1, size1, start2, size2) ({ \ > + typeof(start1) __start1 = (start1); \ > + typeof(size1) __size1 = (size1); \ > + typeof(start2) __start2 = (start2); \ > + typeof(size2) __size2 = (size2); \ > + __start1 < __start2 + __size2 && __start1 + __size1 > __start2; \ > +}) > + > static bool fb_do_apertures_overlap(struct fb_info *gen, struct fb_info *hw) > { > - /* is the generic aperture base the same as the HW one */ > - if (gen->aperture_base == hw->aperture_base) > - return true; > - /* is the generic aperture base inside the hw base->hw base+size */ > - if (gen->aperture_base > hw->aperture_base && gen->aperture_base <= hw->aperture_base + hw->aperture_size) > - return true; > - return false; > + return ranges_overlap(gen->aperture_base, gen->aperture_size, > + hw->aperture_base, hw->aperture_size); > } > /** > * register_framebuffer - registers a frame buffer device -- 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/