linux-kernel - Re: [PATCH 1/2] soundwire: intel: uniquify debug message

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Message-ID: <15ef4ec4-14ae-27fc-919d-b0933454455f@linux.intel.com>
Date:   Mon, 13 Jun 2022 14:21:31 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     alsa-devel@...a-project.org, vinod.koul@...aro.org, tiwai@...e.de,
        linux-kernel@...r.kernel.org, vkoul@...nel.org, broonie@...nel.org,
        srinivas.kandagatla@...aro.org, sanyog.r.kale@...el.com,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        bard.liao@...el.com
Subject: Re: [PATCH 1/2] soundwire: intel: uniquify debug message


>>>>>> @@ -1549,8 +1549,8 @@ static int __maybe_unused intel_pm_prepare(struct device *dev)
>>>>>>  	int ret;
>>>>>>  
>>>>>>  	if (bus->prop.hw_disabled || !sdw->startup_done) {
>>>>>> -		dev_dbg(dev, "SoundWire master %d is disabled or not-started, ignoring\n",
>>>>>> -			bus->link_id);
>>>>>> +		dev_dbg(dev, "%s: SoundWire master %d is disabled or not-started, ignoring\n",
>>>>>> +			__func__, bus->link_id);
>>>>>
>>>>> Not needed, it is provided automatically if you ask the kernel for this.
>>>>> Same for all other instances in this patch.
>>>>
>>>> provided how? Your comment is a bit cryptic here.
>>>
>>> the dynamic debug code in the kernel already adds the function name
>>> where the message was sent from, if you want to know this in userspace.
>>> Please read the documentation for details (I think the key is the 'f'
>>> flag to be enabled in userspace).
>>>
>>> So adding __func__ to dev_dbg() calls are redundant and never needed.
>>
>> Oh wow, I had no idea - and I am not the only one :-)
>>
>> Here's what I get with a grep on the kernel code
>>
>> git grep __func__ | grep dev_dbg | wc -l
>>
>> 3122
>>
>>
>> Doing this for sound/ gives me 356, and that's for single-line logs only.
>>
>> There's clearly something that was missed by tons of people.
> 
> Yes, it's not commonly known so cleanups are always welcome.  Perhaps
> some of those usages predate the feature being added as well.

Yep, looks like no one in our team knew about this. We've changed our
scripts and I started cleaning this up, changes will be posted upstream
soon.

https://github.com/thesofproject/linux/pull/3695

This patch will be reverted in our tree, completely unnecessary indeed.