From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752450AbdGMRmk (ORCPT ); Thu, 13 Jul 2017 13:42:40 -0400 Received: from mga04.intel.com ([192.55.52.120]:60227 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751017AbdGMRmj (ORCPT ); Thu, 13 Jul 2017 13:42:39 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,354,1496127600"; d="scan'208";a="111004587" Date: Thu, 13 Jul 2017 20:42:32 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: =?iso-8859-1?Q?St=E9phane?= Marchesin Cc: Matthias Kaehlcke , "dri-devel@lists.freedesktop.org" , David Airlie , intel-gfx , Linux Kernel Mailing List , Michael Davidson , Grant Grundler , Greg Hackmann , Daniel Vetter Subject: Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Message-ID: <20170713174232.GK12629@intel.com> References: <20170420215605.176722-1-mka@chromium.org> <20170505172636.GA128305@google.com> <20170505174043.GK12629@intel.com> <20170713101351.GS12629@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 13, 2017 at 09:23:11AM -0700, Stéphane Marchesin wrote: > On Thu, Jul 13, 2017 at 3:13 AM, Ville Syrjälä > wrote: > > On Wed, Jul 12, 2017 at 07:28:14PM -0700, Stéphane Marchesin wrote: > >> On Fri, May 5, 2017 at 10:40 AM, Ville Syrjälä > >> wrote: > >> > > >> > On Fri, May 05, 2017 at 10:26:36AM -0700, Matthias Kaehlcke wrote: > >> > > El Thu, Apr 20, 2017 at 02:56:05PM -0700 Matthias Kaehlcke ha dit: > >> > > > >> > > > In several instances the driver passes an 'enum pipe' value to a > >> > > > function expecting an 'enum transcoder' and viceversa. Since PIPE_x and > >> > > > TRANSCODER_x have the same values this doesn't cause functional > >> > > > problems. Still it is incorrect and causes clang to generate warnings > >> > > > like this: > >> > > > > >> > > > drivers/gpu/drm/i915/intel_display.c:1844:34: warning: implicit > >> > > > conversion from enumeration type 'enum transcoder' to different > >> > > > enumeration type 'enum pipe' [-Wenum-conversion] > >> > > > assert_fdi_rx_enabled(dev_priv, TRANSCODER_A); > >> > > > > >> > > > Change the code to pass values of the type expected by the callee. > >> > > > > >> > > > Signed-off-by: Matthias Kaehlcke > >> > > > --- > >> > > > drivers/gpu/drm/i915/intel_display.c | 4 ++-- > >> > > > drivers/gpu/drm/i915/intel_dp.c | 6 ++++-- > >> > > > drivers/gpu/drm/i915/intel_hdmi.c | 6 ++++-- > >> > > > drivers/gpu/drm/i915/intel_sdvo.c | 6 ++++-- > >> > > > 4 files changed, 14 insertions(+), 8 deletions(-) > >> > > > >> > > Ping, any comments on this patch? > >> > > >> > I'm not convinced the patch is making things any better really. To > >> > fix this really properly, I think we'd need to introduce a new enum > >> > pch_transcoder and thus avoid the confusion of which type of > >> > transcoder we're talking about. Currently most places expect an > >> > enum pipe when dealing with PCH transcoders, and enum transcoder > >> > when dealing with CPU transcoders. But there are some exceptions > >> > of course. > >> > >> > >> I don't follow -- these functions take an enum transcoder; what's > >> wrong about passing what they expect? It seems like what you are > >> asking for has nothing to do with the warning here... > > > > There's a warning? I don't get any. > > Yup, clang generates a warning. > > > > > Anyways, I just don't see much point in blindly changing the types > > because it doesn't actually solve the underlying confusion for human > > readers. It might even make it worse, not sure. > > The function expects type A, you pass type B, how can that ever be the > right thing to do? Because maybe the function should be taking in type B instead. -- Ville Syrjälä Intel OTC