Re: [PATCH 1/2] lib/vsprintf: Add support for generic FourCCs by extending %p4cc

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, Mar 12, 2025 at 07:35:54PM +0000, Aditya Garg wrote:
> > On 13 Mar 2025, at 12:58 AM, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > On Wed, Mar 12, 2025 at 07:14:36PM +0000, Aditya Garg wrote:
> >>>> On 12 Mar 2025, at 9:05 PM, Sven Peter <sven@svenpeter.dev> wrote:
> >>> On Wed, Mar 12, 2025, at 13:03, Aditya Garg wrote:

...

> >>> I don't have a strong opinion either way: for SMC I just need to print
> >>> FourCC keys for debugging / information in a few places.
> >>> 
> >>> I'm preparing the SMC driver for upstreaming again (after a two year delay :-()
> >>> and was just going to use macros to print the SMC FourCC keys similar to
> >>> DRM_MODE_FMT/DRM_MODE_ARG for now to keep the series smaller and revisit
> >>> the topic later.
> >>> 
> >>> Right now I have these in my local tree (only compile tested so far):
> >>> 
> >>> #define SMC_KEY_FMT "%c%c%c%c (0x%08x)"
> >>> #define SMC_KEY_ARG(k) (k)>>24, (k)>>16, (k)>>8, (k), (k)
> >> 
> >> That seems to be a nice alternative, which I guess Thomas was also suggesting.
> > 
> > I don't think it's "nice". Each of the approaches has pros and cons.
> 
> I would prefer vsprintf, but if it's not there, that remains as nice right?

Nope, it remains us with the only approach (besides copy'n'paste everywhere
which is error prone).

> > You can start from bloat-o-meter here and compare it with your %p extension.
> > 
> > Also, can you show the bloat-o-meter output for the vsprintf.c?
> 
> vsprintf isn't a kernel module, is it? I'll have to compile a new kernel I guess.

You can just compile one file. We need an object out of it, we don't it to be
linked.

> >>> which are then used like this:
> >>> 
> >>>   dev_info(dev,
> >>>       "Initialized (%d keys " SMC_KEY_FMT " .. " SMC_KEY_FMT ")\n",
> >>>        smc->key_count, SMC_KEY_ARG(smc->first_key),
> >>>        SMC_KEY_ARG(smc->last_key));

-- 
With Best Regards,
Andy Shevchenko