Re: [PATCH 06/14] [media] cx18: Use current logging styles

[Joe Perches <joe@perches.com>]

On Sat, 2011-08-27 at 09:28 -0400, Andy Walls wrote:
> On Wed, 2011-08-24 at 14:42 -0700, Joe Perches wrote:
> > On Wed, 2011-08-24 at 06:34 -0400, Andy Walls wrote:
> > > On Sun, 2011-08-21 at 15:56 -0700, Joe Perches wrote:
> > > > Add pr_fmt.
> > > > Convert printks to pr_<level>.
> > > > Convert printks without KERN_<level> to appropriate pr_<level>.
> > > > Removed embedded prefixes when pr_fmt was added.
> > > > Use ##__VA_ARGS__ for variadic macros.
> > > > Coalesce format strings.
> > > 1. It is important to preserve the per-card prefixes emitted by the
> > > driver: cx18-0, cx18-1, cx18-2, etc.  With a quick skim, I think your
> > > change preserves the format of all output messages (except removing
> > > periods).  Can you confirm this?
> > Here's the output diff of
> > strings built-in.o | grep "^<.>" | sort
> > new and old
[]
> Yuck.
> > > 2. PLease don't add a pr_fmt() #define to exevry file.  Just put one
> > > where all the other CX18_*() macros are defined.  Every file picks those
> > > up.
> > It's not the first #include of every file.
> > printk.h has a default #define pr_fmt(fmt) fmt
> Well then don't use "pr_fmt(fmt)" in cx18, if it overloads a define
> somewhere else in the kernel and has a dependency on its order relative
> to #include statements.  That sort of thing just ups maintenance hours
> later.  That's not a good trade off for subjectively better log
> messages.
> Won't redifining the 'pr_fmt(fmt)' generate preprocessor warnings
> anyway?

No.

Andy, I fully understand how this stuff works.
You apparently don't (yet).

Look at include/linux/printk.h

#ifndef pr_fmt
#define pr_fmt(fmt) fmt
#endif

A default empty define is used when one
is not specified before printk.h is
included.  kernel.h includes printk.h

v4l2_<level> uses the "name" of the video
device in its output.  That name may not
be the same name as the module.