Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788AbbFYGwB (ORCPT ); Thu, 25 Jun 2015 02:52:01 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:35692 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993AbbFYGvx (ORCPT ); Thu, 25 Jun 2015 02:51:53 -0400 Date: Thu, 25 Jun 2015 08:51:47 +0200 From: Ingo Molnar To: "Luis R. Rodriguez" Cc: bp@suse.de, andy@silverblocksystems.net, mchehab@osg.samsung.com, dledford@redhat.com, fengguang.wu@intel.com, linux-media@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, "Luis R. Rodriguez" Subject: Re: [PATCH v2 2/2] x86/mm/pat, drivers/media/ivtv: move pat warn and replace WARN() with pr_warn() Message-ID: <20150625065147.GB5339@gmail.com> References: <1435166600-11956-1-git-send-email-mcgrof@do-not-panic.com> <1435166600-11956-3-git-send-email-mcgrof@do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1435166600-11956-3-git-send-email-mcgrof@do-not-panic.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2388 Lines: 65 * Luis R. Rodriguez wrote: > From: "Luis R. Rodriguez" > > On built-in kernels this warning will always splat as this is part > of the module init. Fix that by shifting the PAT requirement check > out under the code that does the "quasi-probe" for the device. This > device driver relies on an existing driver to find its own devices, > it looks for that device driver and its own found devices, then > uses driver_for_each_device() to try to see if it can probe each of > those devices as a frambuffer device with ivtvfb_init_card(). We > tuck the PAT requiremenet check then on the ivtvfb_init_card() > call making the check at least require an ivtv device present > before complaining. > > Reported-by: Fengguang Wu [0-day test robot] > Signed-off-by: Luis R. Rodriguez > --- > drivers/media/pci/ivtv/ivtvfb.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/pci/ivtv/ivtvfb.c b/drivers/media/pci/ivtv/ivtvfb.c > index 4cb365d..8b95eef 100644 > --- a/drivers/media/pci/ivtv/ivtvfb.c > +++ b/drivers/media/pci/ivtv/ivtvfb.c > @@ -38,6 +38,8 @@ > Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA > */ > > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > #include > #include > #include > @@ -1171,6 +1173,13 @@ static int ivtvfb_init_card(struct ivtv *itv) > { > int rc; > > +#ifdef CONFIG_X86_64 > + if (pat_enabled()) { > + pr_warn("ivtvfb needs PAT disabled, boot with nopat kernel parameter\n"); > + return -ENODEV; > + } > +#endif > + > if (itv->osd_info) { > IVTVFB_ERR("Card %d already initialised\n", ivtvfb_card_id); > return -EBUSY; Same argument as for ipath: why not make arch_phys_wc_add() fail on PAT and return -1, and check it in arch_phys_wc_del()? That way we don't do anything drastic, the remaining few drivers still keep working (albeit suboptimally - can be worked around with the 'nopat' boot option) - yet we've reduced the use of MTRRs drastically. Thanks, 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/