From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753171Ab1ITKyh (ORCPT ); Tue, 20 Sep 2011 06:54:37 -0400 Received: from perceval.ideasonboard.com ([95.142.166.194]:58621 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874Ab1ITKyf (ORCPT ); Tue, 20 Sep 2011 06:54:35 -0400 From: Laurent Pinchart To: "Roedel, Joerg" Subject: Re: [PATCH] iommu/omap: Fix build error with !IOMMU_SUPPORT Date: Tue, 20 Sep 2011 12:54:38 +0200 User-Agent: KMail/1.13.7 (Linux/3.0.3-gentoo; KDE/4.7.1; x86_64; ; ) Cc: "linux-omap@vger.kernel.org" , "Ohad Ben-Cohen" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" References: <1316009259-18052-1-git-send-email-joerg.roedel@amd.com> <201109180202.23123.laurent.pinchart@ideasonboard.com> <20110920100146.GA2078@amd.com> In-Reply-To: <20110920100146.GA2078@amd.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201109201254.39542.laurent.pinchart@ideasonboard.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joerg, On Tuesday 20 September 2011 12:01:46 Roedel, Joerg wrote: > On Sat, Sep 17, 2011 at 08:02:22PM -0400, Laurent Pinchart wrote: > > On Wednesday 14 September 2011 16:07:39 Joerg Roedel wrote: > > > Without this patch it is possible to select the VIDEO_OMAP3 > > > driver which then selects OMAP_IOVMM. But the omap iommu > > > driver is not compiled without IOMMU_SUPPORT enabled. Fix > > > that by forcing OMAP_IOMMU and OMAP_IOVMM are enabled before > > > VIDEO_OMAP3 can be selected. > > > > What about making VIDEO_OMAP3 select IOMMU_SUPPORT instead then ? Your > > patch would make the OMAP3 ISP driver disappear from the menu until > > IOMMU_SUPPORT gets turned on, which can confuse users. > > Using 'depends on' rather then 'selects' is common standard in Kconfig. > You can't select PCI drivers without selecting PCI first, for example. You wouldn't expect a PCI driver to work without PCI support. My concern is that most OMAP3 ISP users won't know that IOMMU supports is required. Feel free to ignore it though :-) > Further selecting whole drivers implicitly isn't a good idea. This can > grow out of control very quickly. -- Regards, Laurent Pinchart