From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 34291CDD54D for ; Wed, 18 Sep 2024 17:26:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 012A210E28B; Wed, 18 Sep 2024 17:26:09 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Wz8qSrSx"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id BABDD10E28B; Wed, 18 Sep 2024 17:26:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726680367; x=1758216367; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=oAzU6jacWPSFfbD7N2+YNUm86tr4pswV9w5y/WuPw04=; b=Wz8qSrSx7MBh0VG/dsNNXnCiPAsj4ZEAPLs+nkoTGYniBlLvuWkJIJpL Qupf/lAeO1vL2cYYGMDza0NQ2THD5VLoH5vZCbJYHv3A8F3dI6Qp1dehv 0n+TDMhdOwKHO9lQcNGTNl+qdyVxf5neFvbrUtQjAiCyhCGfNj42h8xE+ ELoWlJ7CDT4j36tOZydA9lq+aHgvnP8DBRxXTnWeWNkEDagNEKALhTv4W eOzDK5lUvhMqdEPeZ8CErfRtw5Hu46grJ6oCxuOPpm1eArM6yMzrzIxt3 TtHi2khIQz//OOOH9mE+hrkuXW2u3UR+ezgbmcjxOnGWLEoRjd38x1mck A==; X-CSE-ConnectionGUID: 4oxVZpL9TrKCHmulHk2JeQ== X-CSE-MsgGUID: E8FOw0goT2i8YlzJ0HSJnA== X-IronPort-AV: E=McAfee;i="6700,10204,11199"; a="25730822" X-IronPort-AV: E=Sophos;i="6.10,239,1719903600"; d="scan'208";a="25730822" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2024 10:26:07 -0700 X-CSE-ConnectionGUID: 7nytcQ0mRrG/sdJj2C9WIQ== X-CSE-MsgGUID: pBAnT4nZQ9mzoEO9Bww4iQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,239,1719903600"; d="scan'208";a="74444114" Received: from bergbenj-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.246.202]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2024 10:26:04 -0700 From: Jani Nikula To: Nathan Chancellor Cc: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Matthew Auld , Rodrigo Vivi , Anshuman Gupta , Andi Shyti , stable@vger.kernel.org Subject: Re: [PATCH 1/5] drm/i915/gem: fix bitwise and logical AND mixup In-Reply-To: <20240918150542.GA4049109@thelio-3990X> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20240918150542.GA4049109@thelio-3990X> Date: Wed, 18 Sep 2024 20:26:00 +0300 Message-ID: <87v7ysan6f.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Wed, 18 Sep 2024, Nathan Chancellor wrote: > On Wed, Sep 18, 2024 at 02:17:44PM +0300, Jani Nikula wrote: >> CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND is an int, defaulting to 250. When >> the wakeref is non-zero, it's either -1 or a dynamically allocated >> pointer, depending on CONFIG_DRM_I915_DEBUG_RUNTIME_PM. It's likely that >> the code works by coincidence with the bitwise AND, but with >> CONFIG_DRM_I915_DEBUG_RUNTIME_PM=y, there's the off chance that the >> condition evaluates to false, and intel_wakeref_auto() doesn't get >> called. Switch to the intended logical AND. >> >> Fixes: ad74457a6b5a ("drm/i915/dgfx: Release mmap on rpm suspend") >> Cc: Matthew Auld >> Cc: Rodrigo Vivi >> Cc: Anshuman Gupta >> Cc: Andi Shyti >> Cc: # v6.1+ >> Signed-off-by: Jani Nikula >> --- >> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >> index 5c72462d1f57..c157ade48c39 100644 >> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >> @@ -1131,7 +1131,7 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) >> GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(bo->resource)); >> } >> >> - if (wakeref & CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) >> + if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) > > This is going to result in a clang warning: > > drivers/gpu/drm/i915/gem/i915_gem_ttm.c:1134:14: error: use of logical '&&' with constant operand [-Werror,-Wconstant-logical-operand] > 1134 | if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) > | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/gpu/drm/i915/gem/i915_gem_ttm.c:1134:14: note: use '&' for a bitwise operation > 1134 | if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) > | ^~ > | & > drivers/gpu/drm/i915/gem/i915_gem_ttm.c:1134:14: note: remove constant to silence this warning > 1134 | if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 1 error generated. > > Consider adding the explicit '!= 0' to make it clear this should be a > boolean expression. Thanks, will be fixed in v2. BR, Jani. > > Cheers, > Nathan > >> intel_wakeref_auto(&to_i915(obj->base.dev)->runtime_pm.userfault_wakeref, >> msecs_to_jiffies_timeout(CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND)); >> >> -- >> 2.39.2 >> -- Jani Nikula, Intel