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 C055DC74A5B for ; Tue, 21 Mar 2023 17:16:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9A6CA10E847; Tue, 21 Mar 2023 17:16:01 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id 599AF10E827; Tue, 21 Mar 2023 17:16:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679418960; x=1710954960; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=/FkBJNWNhYD2NcqVJ8iNkyIEhSBftkt9bIvW7zOzZ68=; b=WlHGrc+rNS4n5sa2PB54dJB1SCVARM7HDJem01mP+lXjw8B1dFjVN5rh /6IoE+1EwPuNxXwZ5kbHUTOSMUAw7ww5AlD6AUGJjLSiXHk3v9w68J2ta lwG+j/xU4IBEjOk7WPW9grvr8AVm4HNDkep8olGdPdaXwrPMUndyI1cVB F/psz/f/n+DsqjDe5I7KuBx0OJQ2aL3xfiEFOH9Id9EkcLcGBYy0TB/zH uPtzmXWzA8IHd0XkHKdo78RMx2gRPUnzO//4ZRerzDgtv80XiiXwhkNmz WCJifvIwtFmSCIG5wIRhivmjJ1rATHfsviyxe0G+H4OmjOffFal5z/1Hg g==; X-IronPort-AV: E=McAfee;i="6600,9927,10656"; a="336512490" X-IronPort-AV: E=Sophos;i="5.98,279,1673942400"; d="scan'208";a="336512490" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2023 10:15:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10656"; a="750673539" X-IronPort-AV: E=Sophos;i="5.98,279,1673942400"; d="scan'208";a="750673539" Received: from rbirkl-mobl.ger.corp.intel.com (HELO intel.com) ([10.251.222.70]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2023 10:15:56 -0700 Date: Tue, 21 Mar 2023 18:15:33 +0100 From: Andi Shyti To: Andi Shyti Subject: Re: [PATCH v2 1/2] drm/i915: Sanitycheck MMIO access early in driver load Message-ID: References: <20230321170936.478631-1-andi.shyti@linux.intel.com> <20230321170936.478631-2-andi.shyti@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230321170936.478631-2-andi.shyti@linux.intel.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andi Shyti , Mika Kuoppala , intel-gfx@lists.freedesktop.org, Stuart Summers , dri-devel@lists.freedesktop.org, Matt Roper Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" > We occasionally see the PCI device in a non-accessible state at the > point the driver is loaded. When this happens, all BAR accesses will > read back as 0xFFFFFFFF. Rather than reading registers and > misinterpreting their (invalid) values, let's specifically check for > 0xFFFFFFFF in a register that cannot have that value to see if the > device is accessible. > > Signed-off-by: Matt Roper > Cc: Mika Kuoppala > Signed-off-by: Andi Shyti Reviewed-by: Andi Shyti Andi