Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752728AbdGMQXg (ORCPT ); Thu, 13 Jul 2017 12:23:36 -0400 Received: from mail-ua0-f182.google.com ([209.85.217.182]:34377 "EHLO mail-ua0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752401AbdGMQXd (ORCPT ); Thu, 13 Jul 2017 12:23:33 -0400 MIME-Version: 1.0 In-Reply-To: <20170713101351.GS12629@intel.com> References: <20170420215605.176722-1-mka@chromium.org> <20170505172636.GA128305@google.com> <20170505174043.GK12629@intel.com> <20170713101351.GS12629@intel.com> From: =?UTF-8?Q?St=C3=A9phane_Marchesin?= Date: Thu, 13 Jul 2017 09:23:11 -0700 X-Google-Sender-Auth: aphvliwKvkvnq88LUUB6s4L88f8 Message-ID: Subject: Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches To: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= Cc: Matthias Kaehlcke , "dri-devel@lists.freedesktop.org" , David Airlie , intel-gfx , Linux Kernel Mailing List , Michael Davidson , Grant Grundler , Greg Hackmann , Daniel Vetter Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6DGO8UB001048 Content-Length: 2569 Lines: 64 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? Stéphane > > -- > Ville Syrjälä > Intel OTC