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Date:   Thu, 05 May 2022 19:50:56 +0200
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Subject: Re: [RFC v1] opp: add config option for debug
Reply-to: frank-w@public-files.de
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Frank Wunderlich <linux@fw-web.de>
CC:     linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>,
        Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
        Stephen Boyd <sboyd@kernel.org>, linux-kernel@vger.kernel.org
From:   Frank Wunderlich <frank-w@public-files.de>
Message-ID: <E08A9747-2F96-42A7-A427-0E00D4075CF0@public-files.de>
Precedence: bulk

Hi,

Am 4=2E Mai 2022 20:24:00 MESZ schrieb Greg Kroah-Hartman <gregkh@linuxfou=
ndation=2Eorg>:
>On Wed, May 04, 2022 at 07:48:23PM +0200, Frank Wunderlich wrote:
>> From: Frank Wunderlich <frank-w@public-files=2Ede>
>>=20
>> Currently OPP debug is enabled by DEBUG_DRIVER option=2E This is
>generic
>> driver debug and opp floods serial console=2E This is annoying if opp
>is
>> not needed so give it an additional config-key=2E
>>=20
>> Signed-off-by: Frank Wunderlich <frank-w@public-files=2Ede>
>> ---
>>  drivers/base/Kconfig | 1 +
>>  drivers/opp/Kconfig  | 7 +++++++
>>  drivers/opp/Makefile | 2 +-
>>  3 files changed, 9 insertions(+), 1 deletion(-)
>>=20
>> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
>> index 6f04b831a5c0=2E=2E8ae826c95d5f 100644
>> --- a/drivers/base/Kconfig
>> +++ b/drivers/base/Kconfig
>> @@ -130,6 +130,7 @@ config DEV_COREDUMP
>>  config DEBUG_DRIVER
>>  	bool "Driver Core verbose debug messages"
>>  	depends on DEBUG_KERNEL
>> +	imply DEBUG_OPP
>
>This should not be needed, otherwise we would have to do that for all
>random driver subsystem in the kernel=2E

Have added this to have same behaviour if anyone sets DEBUG_DRIVER via def=
config=2E Else this is disabled by default=2E

>>  	help
>>  	  Say Y here if you want the Driver core to produce a bunch of
>>  	  debug messages to the system log=2E Select this if you are having a
>> diff --git a/drivers/opp/Kconfig b/drivers/opp/Kconfig
>> index e8ce47b32735=2E=2E6a2d2c6c1143 100644
>> --- a/drivers/opp/Kconfig
>> +++ b/drivers/opp/Kconfig
>> @@ -12,3 +12,10 @@ config PM_OPP
>>  	  representing individual voltage domains and provides SOC
>>  	  implementations a ready to use framework to manage OPPs=2E
>>  	  For more information, read <file:Documentation/power/opp=2Erst>
>> +
>> +menu "Operating Performance Points (OPP)"
>> +config DEBUG_OPP
>> +	bool "Debug Operating Performance Points"
>> +	help
>> +	  enable opp debugging
>> +endmenu
>> diff --git a/drivers/opp/Makefile b/drivers/opp/Makefile
>> index f65ed5985bb4=2E=2E2589915eef95 100644
>> --- a/drivers/opp/Makefile
>> +++ b/drivers/opp/Makefile
>> @@ -1,5 +1,5 @@
>>  # SPDX-License-Identifier: GPL-2=2E0-only
>> -ccflags-$(CONFIG_DEBUG_DRIVER)	:=3D -DDEBUG
>> +ccflags-$(CONFIG_DEBUG_OPP)	:=3D -DDEBUG
>
>This feels wrong, you shouldn't need a -DDEBUG for anything if all is
>going correctly=2E  Why is opp so odd this way?  Just use the normal
>dev_dbg() macros and all will be fine, nothing special should be needed
>at all=2E

I have looked more into it,just wanted to get driver debug (probing/bindin=
g) and dev_dbg messages without the opp spam (floods serial console)=2E

>And don't use a config option for it either, no one will turn it on, it
>needs to "just work" for all systems=2E

Config option is to enable if needed and not via driver-debug=2E

>thanks,
>
>greg k-h


regards Frank