From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: Re: [PATCH] drm/i915: Silence build error with UBSAN Date: Tue, 16 Oct 2018 14:48:13 +0300 Message-ID: <87murekt8i.fsf@intel.com> References: <20181015203410.155997-1-swboyd@chromium.org> <87sh16ky9d.fsf@intel.com> <153968444736.22931.7687263957265816381@skylake-alporthouse-com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <153968444736.22931.7687263957265816381@skylake-alporthouse-com> Sender: linux-kernel-owner@vger.kernel.org To: Chris Wilson , Joonas Lahtinen , Rodrigo Vivi , Stephen Boyd Cc: Michal Marek , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Masahiro Yamada , Andrey Ryabinin List-Id: dri-devel@lists.freedesktop.org On Tue, 16 Oct 2018, Chris Wilson wrote: > Quoting Jani Nikula (2018-10-16 10:59:42) >> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c >> index f27dbe26bcc1..897d5a557d88 100644 >> --- a/drivers/gpu/drm/i915/intel_engine_cs.c >> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c >> @@ -461,12 +461,14 @@ static void intel_engine_init_batch_pool(struct intel_engine_cs *engine) >> i915_gem_batch_pool_init(&engine->batch_pool, engine); >> } >> >> +#define IS_POWER_OF_2(n) ((n) != 0 && ((n) & ((n) - 1)) == 0) >> + >> static void intel_engine_init_execlist(struct intel_engine_cs *engine) >> { >> struct intel_engine_execlists * const execlists = &engine->execlists; >> >> execlists->port_mask = 1; >> - BUILD_BUG_ON_NOT_POWER_OF_2(execlists_num_ports(execlists)); >> + GEM_BUG_ON(!IS_POWER_OF_2(execlists_num_ports(execlists))); > > That should be happy with is_power_of_2() from log2.h D'oh. Thanks. I was sure there was one, I looked for it, but my git greps were all upper case. :/ I'll spin a new version, along with the other clang build fix. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center