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 09B58C5516D for ; Fri, 31 Jul 2026 11:23:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C502010F21F; Fri, 31 Jul 2026 11:23:00 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="FOREZIZT"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1A66310F21F for ; Fri, 31 Jul 2026 11:22:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1785496979; x=1817032979; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=kMwGUDAu/de3tkt3jVhD/aGmQuGBHseVSfGHs90L+h4=; b=FOREZIZTj7N0PGXOSf4ImGCBfAtyY08xs+K7ollyznhDz50FXksKQamc 2pcR7XPkp6BBhChmv3/X/1ssCEKXSZFcfnVWzmv4wBcwja5cqUAIscMnN P3wsMo6YksvPe+0iG6OD9EjQWHcCD8wWCh3oAifrm2iMR/pbA7p7Bfgnj OABGHUBxyVrroPTlGT6G3ZfX+HNCC2A5is746Of3j+YtgD1hVzcKmKq6r yufgSlKxE6Ico7Dk3K3Y99lGzOCqDSzaqChUTVNDwO6WrOJ1O265vXFqv J/XwgEMZzsHfqUoGsmoMIUGoVMAyzaq5XGCVmz9ZSNZ9Co6DDV6D+8hze Q==; X-CSE-ConnectionGUID: xy5onDi5ReqUNUFxIlU0MA== X-CSE-MsgGUID: Ua0tNr7tTYCn0aWoSJiswQ== X-IronPort-AV: E=McAfee;i="6800,10657,11860"; a="89801007" X-IronPort-AV: E=Sophos;i="6.25,196,1779174000"; d="scan'208";a="89801007" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2026 04:22:58 -0700 X-CSE-ConnectionGUID: 4LtVhJbuTuSUwtChfnsZtg== X-CSE-MsgGUID: 6x7TqhZFQUGl33kkRcc3jA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,196,1779174000"; d="scan'208";a="254250054" Received: from slindbla-desk.ger.corp.intel.com (HELO [10.245.244.78]) ([10.245.244.78]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2026 04:22:57 -0700 Message-ID: <7477c473-6027-4941-8a0d-fa6b90dd477d@intel.com> Date: Fri, 31 Jul 2026 12:22:55 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 3/3] drm/xe/guc_ads: use uncached mapping for UM queue BO To: Jia Yao , intel-xe@lists.freedesktop.org Cc: gwan-gyeong.mun@intel.com, stable@vger.kernel.org References: <20260722053410.2767369-1-jia.yao@intel.com> <20260730232712.517989-1-jia.yao@intel.com> <20260730232712.517989-4-jia.yao@intel.com> Content-Language: en-GB From: Matthew Auld In-Reply-To: <20260730232712.517989-4-jia.yao@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 31/07/2026 00:27, Jia Yao wrote: > The HW unit that writes fault descriptors into the UM queue ring buffer > may not be coherent with the CPU cache. If a descriptor write is still > sitting in a GPU L3 cache line when GuC reads the slot, GuC sees the > stale (all-zero) content from DRAM and forwards an invalid descriptor to > the driver (Faulted Address = 0, ASID = 0). > > Mark the UM queue BO as uncached (XE_BO_FLAG_NEEDS_UC) so that writes > bypass the cache and are immediately visible to GuC. > Did you mean to drop the fixes tag here? Fixes: 9c57bc08652a ("drm/xe/lnl: Drop force_probe requirement") Cc: # v6.12+ > Cc: Gwan-gyeong Mun > Cc: Matthew Auld > Signed-off-by: Jia Yao Reviewed-by: Matthew Auld