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Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches

From Stéphane Marchesin <stephane.marchesin@gmail.com>
Newsgroups linux.kernel
Subject Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches
Date 2017-07-13 22:00 +0200
Message-ID <u2Srh-1rA-37@gated-at.bofh.it> (permalink)
References (2 earlier) <tDPwC-4T3-7@gated-at.bofh.it> <u2C38-84q-27@gated-at.bofh.it> <u2JnY-4lu-21@gated-at.bofh.it> <u2Pa2-7UJ-21@gated-at.bofh.it> <u2Qps-cO-15@gated-at.bofh.it>
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On Thu, Jul 13, 2017 at 10:42 AM, Ville Syrjälä
<ville.syrjala@linux.intel.com> wrote:
> On Thu, Jul 13, 2017 at 09:23:11AM -0700, Stéphane Marchesin wrote:
>> On Thu, Jul 13, 2017 at 3:13 AM, Ville Syrjälä
>> <ville.syrjala@linux.intel.com> 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
>> >> <ville.syrjala@linux.intel.com> 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 <mka@chromium.org>
>> >> > > > ---
>> >> > > >  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.

So, if you think this is wrong, can you fix this warning in a way that
you'd like?

Stéphane

>
> --
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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Thread

Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Stéphane Marchesin <marcheu@chromium.org> - 2017-07-13 04:30 +0200
  Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum  mismatches Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-07-13 12:20 +0200
    Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum  mismatches Daniel Vetter <daniel@ffwll.ch> - 2017-07-13 14:30 +0200
    Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Stéphane Marchesin <marcheu@chromium.org> - 2017-07-13 18:30 +0200
      Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum  mismatches Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-07-13 19:50 +0200
        Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Stéphane Marchesin <stephane.marchesin@gmail.com> - 2017-07-13 22:00 +0200
          Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Jani Nikula <jani.nikula@linux.intel.com> - 2017-07-14 11:10 +0200
            Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Grant Grundler <grundler@chromium.org> - 2017-07-14 19:40 +0200
              Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Daniel Vetter <daniel@ffwll.ch> - 2017-07-14 23:40 +0200
                Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum mismatches Grant Grundler <grundler@chromium.org> - 2017-07-15 00:50 +0200
                Re: [Intel-gfx] [PATCH RESEND] drm/i915: Fix pipe/transcoder enum  mismatches Matthias Kaehlcke <mka@chromium.org> - 2017-07-15 01:40 +0200

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