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 X-Spam-Level: X-Spam-Status: No, score=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D22B8C433DB for ; Mon, 8 Feb 2021 10:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D4FF64E7A for ; Mon, 8 Feb 2021 10:56:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232630AbhBHK4R (ORCPT ); Mon, 8 Feb 2021 05:56:17 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:12498 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232625AbhBHKwy (ORCPT ); Mon, 8 Feb 2021 05:52:54 -0500 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4DZ2qk2zrjzjKdR; Mon, 8 Feb 2021 18:50:42 +0800 (CST) Received: from [127.0.0.1] (10.69.38.196) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.498.0; Mon, 8 Feb 2021 18:51:58 +0800 Subject: Re: [PATCH 2/4] hwmon: Use subdir-ccflags-* to inherit debug flag To: Bjorn Helgaas , Guenter Roeck CC: , , , , , , , , , , , , , , References: <20210205200859.GA193526@bjorn-Precision-5520> From: Yicong Yang Message-ID: <2513dca6-2460-5f9d-c482-ff2c179d9c94@hisilicon.com> Date: Mon, 8 Feb 2021 18:51:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: <20210205200859.GA193526@bjorn-Precision-5520> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.69.38.196] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On 2021/2/6 4:08, Bjorn Helgaas wrote: > On Fri, Feb 05, 2021 at 10:28:32AM -0800, Guenter Roeck wrote: >> On Fri, Feb 05, 2021 at 05:44:13PM +0800, Yicong Yang wrote: >>> From: Junhao He >>> >>> Use subdir-ccflags-* instead of ccflags-* to inherit the debug >>> settings from Kconfig when traversing subdirectories. >>> >>> Suggested-by: Bjorn Helgaas >>> Signed-off-by: Junhao He >>> Signed-off-by: Yicong Yang >> >> What problem does this fix ? Maybe I am missing it, but I don't see >> DEBUG being used in a subdirectory of drivers/hwmon. > > It's my fault for raising this question [1]. Yicong fixed a real > problem in drivers/pci, where we are currently using > > ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG > > so CONFIG_PCI_DEBUG=y turns on debug in drivers/pci, but not in the > subdirectories. That's surprising to users. > > So my question was whether we should default to using subdir-ccflags > for -DDEBUG in general, and only use ccflags when we have > subdirectories that have their own debug options, e.g., > > drivers/i2c/Makefile:ccflags-$(CONFIG_I2C_DEBUG_CORE) := -DDEBUG > drivers/i2c/algos/Makefile:ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG > drivers/i2c/busses/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG > drivers/i2c/muxes/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG > > I mentioned drivers/hwmon along with a few others that have > subdirectories, do not have per-subdirectory debug options, and use > ccflags. I didn't try to determine whether those subdirectories > currently use -DDEBUG. > > In the case of drivers/hwmon, several drivers do use pr_debug(), > and CONFIG_HWMON_DEBUG_CHIP=y turns those on. But if somebody > were to add pr_debug() to drivers/hwmon/occ/common.c, for example, > CONFIG_HWMON_DEBUG_CHIP=y would *not* turn it on. That sounds > surprising to me, but if that's what you intend, that's totally fine. i thought CONFIG_HWMON_DEBUG_CHIP=y means to enable debug including the subdirectories, so use subdir-ccflags-* will make sure the debug message on in the subdirectories, if there will be. please let me know if i understand wrong. Thanks, Yicong > > [1] https://lore.kernel.org/r/20210204161048.GA68790@bjorn-Precision-5520 > >>> --- >>> drivers/hwmon/Makefile | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile >>> index 09a86c5..1c0c089 100644 >>> --- a/drivers/hwmon/Makefile >>> +++ b/drivers/hwmon/Makefile >>> @@ -201,5 +201,5 @@ obj-$(CONFIG_SENSORS_XGENE) += xgene-hwmon.o >>> obj-$(CONFIG_SENSORS_OCC) += occ/ >>> obj-$(CONFIG_PMBUS) += pmbus/ >>> >>> -ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG >>> +subdir-ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG >>> >>> -- >>> 2.8.1 >>> > > . >