From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Perches <joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
Subject: RFC: Use dynamic-debug with pr_debug when -DDEBUG is set
Date: Wed, 10 Aug 2011 17:01:37 -0700
Message-ID: <1313020897.11924.137.camel@Joe-Laptop>
References: <CAJfuBxwq3xw3MZU01rwzg0NAnnxNoLrC2x0QXnj+2pD-6gkR4g@mail.gmail.com>
	 <1313020216.11924.129.camel@Joe-Laptop>
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To: Jim Cromie <jim.cromie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Jason Baron <jbaron-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
List-Id: linux-i2c@vger.kernel.org

On Wed, 2011-08-10 at 16:50 -0700, Joe Perches wrote:
> On Wed, 2011-08-10 at 15:06 -0600, Jim Cromie wrote:
> > scx200_acb has several pr_debugs, but theyre not available via dynamic-debug
> > Ive been unable to figure out why.
> > Any ideas ?
> -DDEBUG forces pr_debug to be output and doesn't
> allow dynamic_debug for those outputs.
> from drivers/i2c/busses/Makefile:
> ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
> from printk.h:
> /* If you are writing a driver, please use dev_dbg instead */
> #if defined(DEBUG)
> #define pr_debug(fmt, ...) \
> 	printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
> #elif defined(CONFIG_DYNAMIC_DEBUG)
> /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
> #define pr_debug(fmt, ...) \
> 	dynamic_pr_debug(fmt, ##__VA_ARGS__)

Perhaps another way to enable pr_debug use
is to reverse the order of dynamic_pr_debug
defines.

ie:  change printk.h:

#if defined(CONFIG_DYNAMIC_DEBUG)
/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
#define pr_debug(fmt, ...) \
	dynamic_pr_debug(fmt, ##__VA_ARGS__)
#elif defined(DEBUG)
#define pr_debug(fmt, ...) \
	printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)

and change dynamic_debug.h:

#define DPRINTK_FLAGS_DEFAULT 0

to:

#if defined DEBUG
#define DPRINTK_FLAGS_DEFAULT DPRINTK_FLAGS_PRINT
#else
#define DPRINT_FLAGS_DEFAULT 0
#endif

That seems pretty sensible to me.  Jason?