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

[Aditya Garg]

> On 13 Mar 2025, at 12:58 AM, Andy Shevchenko <andriy.shevchenko at 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 at 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?

> 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.
> 
>>> 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
> 
>