From: Guenter Roeck <linux@roeck-us.net>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Yicong Yang <yangyicong@hisilicon.com>,
gregkh@linuxfoundation.org, jdelvare@suse.com,
giometti@enneenne.com, abbotti@mev.co.uk,
hsweeten@visionengravers.com, kw@linux.com,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-hwmon@vger.kernel.org, devel@driverdev.osuosl.org,
linux-kbuild@vger.kernel.org, masahiroy@kernel.org,
michal.lkml@markovi.net, prime.zeng@huawei.com,
linuxarm@openeuler.org
Subject: Re: [PATCH 2/4] hwmon: Use subdir-ccflags-* to inherit debug flag
Date: Mon, 8 Feb 2021 13:00:41 -0800 [thread overview]
Message-ID: <28707cb4-8f2d-2864-4efe-749ca7ee494c@roeck-us.net> (raw)
In-Reply-To: <20210205200859.GA193526@bjorn-Precision-5520>
On 2/5/21 12:08 PM, 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 <hejunhao2@hisilicon.com>
>>>
>>> Use subdir-ccflags-* instead of ccflags-* to inherit the debug
>>> settings from Kconfig when traversing subdirectories.
>>>
>>> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
>>> Signed-off-by: Junhao He <hejunhao2@hisilicon.com>
>>> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
>>
>> 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-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
>
> I mentioned drivers/hwmon along with a few others that have
> subdirectories, do not have per-subdirectory debug options, and use
> ccflags. I didn't try to determine whether those subdirectories
> currently use -DDEBUG.
>
> In the case of drivers/hwmon, several drivers do use pr_debug(),
> and CONFIG_HWMON_DEBUG_CHIP=y turns those on. But if somebody
> were to add pr_debug() to drivers/hwmon/occ/common.c, for example,
> CONFIG_HWMON_DEBUG_CHIP=y would *not* turn it on. That sounds
> surprising to me, but if that's what you intend, that's totally fine.
>
That does make sense, but that explanation is missing from the
description.
Guenter
> [1] https://lore.kernel.org/r/20210204161048.GA68790@bjorn-Precision-5520
>
>>> ---
>>> drivers/hwmon/Makefile | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>>> index 09a86c5..1c0c089 100644
>>> --- a/drivers/hwmon/Makefile
>>> +++ b/drivers/hwmon/Makefile
>>> @@ -201,5 +201,5 @@ obj-$(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
>>>
next prev parent reply other threads:[~2021-02-08 21:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 9:44 [PATCH 0/4] Use subdir-ccflags-* to inherit debug flag Yicong Yang
2021-02-05 9:44 ` [PATCH 1/4] driver core: " Yicong Yang
2021-02-05 9:53 ` Greg KH
2021-02-08 10:44 ` Yicong Yang
2021-02-08 10:47 ` Greg KH
2021-02-08 13:09 ` Yicong Yang
2021-02-10 11:42 ` Daniel Thompson
2021-02-24 9:56 ` Yicong Yang
2021-02-05 9:44 ` [PATCH 2/4] hwmon: " Yicong Yang
2021-02-05 18:28 ` Guenter Roeck
2021-02-05 20:08 ` Bjorn Helgaas
2021-02-08 10:51 ` Yicong Yang
2021-02-08 21:00 ` Guenter Roeck [this message]
2021-02-05 9:44 ` [PATCH 3/4] pps: " Yicong Yang
2021-02-05 9:44 ` [PATCH 4/4] staging: comedi: " Yicong Yang
2021-02-05 9:54 ` Greg KH
2021-02-06 0:52 ` Masahiro Yamada
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