From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751441AbdJEN7k (ORCPT ); Thu, 5 Oct 2017 09:59:40 -0400 Received: from esa8.dell-outbound.iphmx.com ([68.232.149.218]:34804 "EHLO esa8.dell-outbound.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750965AbdJEN7i (ORCPT ); Thu, 5 Oct 2017 09:59:38 -0400 From: X-LoopCount0: from 10.166.132.172 X-IronPort-AV: E=Sophos;i="5.42,481,1500958800"; d="scan'208";a="156366300" X-DLP: DLP_GlobalPCIDSS To: , CC: , , , , , , , , Subject: RE: [PATCH v4 05/14] platform/x86: dell-wmi-descriptor: split WMI descriptor into it's own driver Thread-Topic: [PATCH v4 05/14] platform/x86: dell-wmi-descriptor: split WMI descriptor into it's own driver Thread-Index: AQHTPWLwy4LaHQCqf0OMYSZFVl7S46LUxiSAgABIpQCAAByzgIAAGr2AgAADFsA= Date: Thu, 5 Oct 2017 13:59:36 +0000 Message-ID: <3be9670de8404523be04e2e319f1c1b3@ausx13mpc120.AMER.DELL.COM> References: <20171005010909.GC25018@fury> <20171005071153.GA31452@fury> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.143.18.86] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v95DxoT3030855 > -----Original Message----- > From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com] > Sent: Thursday, October 5, 2017 3:48 AM > To: Darren Hart > Cc: Limonciello, Mario ; LKML kernel@vger.kernel.org>; Platform Driver x86@vger.kernel.org>; Andy Lutomirski ; > quasisec@google.com; Pali Rohár ; Rafael J. Wysocki > ; mjg59@google.com; Christoph Hellwig ; > Greg KH > Subject: Re: [PATCH v4 05/14] platform/x86: dell-wmi-descriptor: split WMI > descriptor into it's own driver > > On Thu, Oct 5, 2017 at 10:11 AM, Darren Hart wrote: > > On Thu, Oct 05, 2017 at 08:29:10AM +0300, Andy Shevchenko wrote: > >> On Thu, Oct 5, 2017 at 4:09 AM, Darren Hart wrote: > > >> > You'll want to add something like: > >> > > >> > #ifdef CONFIG_DELL_WMI_DESCRIPTOR_MODULE > >> > if (request_module("dell_wmi_descriptor")) > >> > /* FAIL */ > >> > #endif > >> > > >> > During init. > >> > >> I don't think #ifdef is needed. > > > > Without the ifdef, we can't distinguish between request_module failing > > to load the module because it isn't available and because it is > > built-in. > > > >> > >> We may just request module. > >> > >> But looking in the code it seems that we simple need to select that > >> module. No request_module will be needed. > > > > The select will ensure the module is built, but there is not guarantee > > to module load order. The intent of the above is to ensure the symbols > > from the required module are loaded. > > > >> Did I miss something? > > > > Or I did :-) Is there something about this module which ensures > > dell_wmi_descriptor is loaded first? > > If there is an optional *run-time* dependency we need to use somelike > request_module(). For example, this is the case for idma64 > (drivers/dma) vs intel-lpss (drivers/mfd). > > If it's mandatory run-time dependency, then we need to add stubs to > the header and select the callee's module in Kconfig. > > In case they are both modules, depmod keeps an ordering. > > So, the corner case here is when the caller is builtin while callee is module. > > This is a bit tricky to add to Kconfig (we also have such cases > between I2C DesignWare and acpi_lpss AFAIR). > > -- > With Best Regards, > Andy Shevchenko So I believe it should be a mandatory runtime dependency due to needing the symbol dell_wmi_get_interface_version. Depmod should be handling this then no?