linux-kernel - Re: [PATCH v2] ALSA: korg1212: cleanup of printk

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Date:	Mon, 24 Nov 2014 18:08:02 +0100
From:	Takashi Iwai <tiwai@...e.de>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	Jaroslav Kysela <perex@...ex.cz>, alsa-devel@...a-project.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ALSA: korg1212: cleanup of printk

At Sun, 23 Nov 2014 13:40:51 +0530,
Sudip Mukherjee wrote:
> 
> From: Sudip Mukherjee <sudip@...torindia.org>
> 
> replaced all references of the debug messages via printk
> with dev_* macro (mostly dev_dbg).
> one reference was changed to pr_err as there the card might have been
> uninitialized.
> 
> this patch will generate warning from checkpatch about broken quoted
> strings. but that was not fixed intentionally to improve the
> readability.
> 
> Signed-off-by: Sudip Mukherjee <sudip@...torindia.org>
> ---
> 
> change in v2: the build warnings of v1 are fixed.
> 
> hi Takashi,
> in your review of v1, you said about some lines which are not ending
> with \n. but i was not able to find them. did i miss them somewhere?

The problem is the one with multiple "\n", for example:

	dev_dbg(korg1212->card->dev, "dspMemPhy = %08x U[%08x], "
		"PlayDataPhy = %08x L[%08x]\n"
		"korg1212: RecDataPhy = %08x L[%08x], "
		"VolumeTablePhy = %08x L[%08x]\n"
		"korg1212: RoutingTablePhy = %08x L[%08x], "
		"AdatTimeCodePhy = %08x L[%08x]\n",

My biggest concern right now is, however, about the unnecessary code
increase by this patch.  Currently, most of debug prints were simply
not built, because of:

>  // ----------------------------------------------------------------------------
> -// Debug Stuff
> -// ----------------------------------------------------------------------------
> -#define K1212_DEBUG_LEVEL		0
> -#if K1212_DEBUG_LEVEL > 0
> -#define K1212_DEBUG_PRINTK(fmt,args...)	printk(KERN_DEBUG fmt,##args)
> -#else
> -#define K1212_DEBUG_PRINTK(fmt,...)
> -#endif
> -#if K1212_DEBUG_LEVEL > 1
> -#define K1212_DEBUG_PRINTK_VERBOSE(fmt,args...)	printk(KERN_DEBUG fmt,##args)
> -#else
> -#define K1212_DEBUG_PRINTK_VERBOSE(fmt,...)
> -#endif

With your patch, now all these codes are compiled.

I have no clear answer what would be the best in such a case.  I'd say
it really depends.  If they are just silly messages that can be
covered in a better way (like ftrace), just get rid of them.  If they
are intended for some good register dumps, then dev_dbg() might make
sense.


Takashi
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