linux-kernel - Re: [PATCH] drm/i915: Mark wait_for_engine() as maybe_unused

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Message-ID: <20170926045410.26imjvhwbo4kvjuv@phenom.ffwll.local>
Date:   Tue, 26 Sep 2017 06:54:10 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     Daniel Vetter <daniel.vetter@...el.com>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        David Airlie <airlied@...ux.ie>,
        Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
        linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        Nick Desaulniers <nick.desaulniers@...il.com>,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/i915: Mark wait_for_engine() as maybe_unused

On Fri, Aug 25, 2017 at 10:09:45AM -0700, Matthias Kaehlcke wrote:
> The only call of wait_for_engine() is wrapped in a GEM_WARN_ON macro,
> which confusingly suppresses the call unless CONFIG_DRM_I915_DEBUG_GEM
> is set.
> 
> According to http://www.spinics.net/lists/intel-gfx/msg128768.html the
> current behavior is correct, even though it's not obvious. Different
> solutions to improve GEM_WARN_ON were discussed, but no conclusion
> was reached.
> 
> Mark wait_for_engine() as maybe_unused to avoid a compiler warning,
> according to the above discussion this is still needed evein if
> GEM_WARN_ON is eventually refactored.
> 
> Reported-by: Nick Desaulniers <nick.desaulniers@...il.com>
> Signed-off-by: Matthias Kaehlcke <mka@...omium.org>

Seems to be taken care of already in

commit cad9946c2a4375386062131858881cfd30fc1b8f
Author: Chris Wilson <chris@...is-wilson.co.uk>
Date:   Sat Aug 26 12:09:33 2017 +0100

    drm/i915: Always sanity check engine state upon idling

Cheers, Daniel
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 969bac8404f1..52d0b7d0082b 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3364,7 +3364,8 @@ static int wait_for_timeline(struct i915_gem_timeline *tl, unsigned int flags)
>  	return 0;
>  }
>  
> -static int wait_for_engine(struct intel_engine_cs *engine, int timeout_ms)
> +static __maybe_unused int wait_for_engine(
> +	struct intel_engine_cs *engine, int timeout_ms)
>  {
>  	return wait_for(intel_engine_is_idle(engine), timeout_ms);
>  }
> -- 
> 2.14.1.342.g6490525c54-goog
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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