From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934465AbcCPTfF (ORCPT ); Wed, 16 Mar 2016 15:35:05 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:36987 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755335AbcCPTfB (ORCPT ); Wed, 16 Mar 2016 15:35:01 -0400 Subject: Re: [PATCH] nouveau: fix nv40_perfctr_next() cleanup regression To: Arnd Bergmann , David Airlie References: <1457965458-3319933-1-git-send-email-arnd@arndb.de> Cc: Ben Skeggs , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org From: Samuel Pitoiset Message-ID: <56E9B561.3060401@gmail.com> Date: Wed, 16 Mar 2016 20:34:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1457965458-3319933-1-git-send-email-arnd@arndb.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reviewed-by: Samuel Pitoiset On 03/14/2016 03:24 PM, Arnd Bergmann wrote: > gcc-6 warns about code in the nouveau driver that is obviously silly: > > drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c: In function 'nv40_perfctr_next': > drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c:62:19: warning: self-comparison always evaluats to false [-Wtautological-compare] > if (pm->sequence != pm->sequence) { > > The behavior was accidentally introduced in a patch described as "This is > purely preparation for upcoming commits, there should be no code changes here.". > As far as I can tell, that was true for the rest of that patch except for > this one function, which has been changed to a NOP. > > This patch restores the original behavior. > > Signed-off-by: Arnd Bergmann > Fixes: 8c1aeaa13954 ("drm/nouveau/pm: cosmetic changes") > --- > drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c b/drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c > index 4bef72a9d106..3fda594700e0 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c > +++ b/drivers/gpu/drm/nouveau/nvkm/engine/pm/nv40.c > @@ -59,9 +59,11 @@ static void > nv40_perfctr_next(struct nvkm_pm *pm, struct nvkm_perfdom *dom) > { > struct nvkm_device *device = pm->engine.subdev.device; > - if (pm->sequence != pm->sequence) { > + struct nv40_pm *nv40pm = container_of(pm, struct nv40_pm, base); > + > + if (nv40pm->sequence != pm->sequence) { > nvkm_wr32(device, 0x400084, 0x00000020); > - pm->sequence = pm->sequence; > + nv40pm->sequence = pm->sequence; > } > } > >