From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752528AbbJTO6m (ORCPT <rfc822;w@1wt.eu>);
	Tue, 20 Oct 2015 10:58:42 -0400
Received: from mga03.intel.com ([134.134.136.65]:39887 "EHLO mga03.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751877AbbJTO6k (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 20 Oct 2015 10:58:40 -0400
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.17,707,1437462000"; 
   d="scan'208";a="798132013"
Date: Tue, 20 Oct 2015 17:58:35 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Andreas Ziegler <andreas.ziegler@fau.de>
Cc: Peter Huewe <peterhuewe@gmx.de>, Marcel Selhorst <tpmdd@selhorst.net>,
        Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
        tpmdd-devel@lists.sourceforge.net,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Valentin Rothberg <rothberg@cs.fau.de>,
        Paul Bolle <pebolle@tiscali.nl>
Subject: Re: tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0
Message-ID: <20151020145835.GA6186@intel.com>
References: <56262A2E.6040602@fau.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <56262A2E.6040602@fau.de>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Oct 20, 2015 at 01:49:02PM +0200, Andreas Ziegler wrote:
> Hi Jarkko,
> 
> your patch "tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0"
> showed up as commit 399235dc6e95 in linux-next today (that is,
> next-20151020). I noticed it because we (a research group from
> Erlangen[0]) are running daily checks on linux-next.
> 
> Your commit creates the following structure of #ifdef blocks in
> drivers/char/tpm/tpm_tis.c following line 1088:
> 
>  #ifdef CONFIG_ACPI
>  ...
>  #ifdef CONFIG_PNP
>  ...
>  #endif
>  ...
>  #endif
> 
> Looking at the definition of CONFIG_ACPI at drivers/acpi/Kconfig, line
> 5, we see that ACPI unconditionally selects PNP, meaning that CONFIG_PNP
> is always enabled if CONFIG_ACPI has been enabled.
> Thus, the inner #ifdef statement can never evaluate to 'false' if the
> outer #ifdef evaluates to true (i.e., CONFIG_ACPI is enabled), and
> hence, the #ifdef is unnecessary.
> 
> The same situation holds for the nested structure following line 1124,
> where the #ifdef CONFIG_PNP at line 1129 is unnecessary.
> 
> Is this correct or did we miss something?

Good catch. Shoud I send a separate fix for this? Thanks for pointing
this out.

> Regards,
> 
> Andreas
> 
> [0] https://cados.cs.fau.de

/Jarkko