[Intel-gfx] [PATCH 1/1] drm/i915/mtl: enable local stolen memory

Andi Shyti andi.shyti at linux.intel.com
Tue Sep 20 22:33:34 UTC 2022


Hi Matt, Lucas,

thanks for your feedback,

> > > +	switch (gms) {
> > > +	case 0x0 ... 0x10:
> > > +		return gms * 32;
> > > +	case 0x20:
> > > +		return 1024;
> > > +	case 0x30:
> > > +		return 1536;
> > > +	case 0x40:
> > > +		return 2048;
> > > +	case 0xf0 ... 0xfe:
> > 
> > just a bit puzzled by the fact that case ranges are not standard
> > and are supported only by GCC, unless, of course, I miss
> > something. Do we still want to use them as they are widely used
> > around the kernel?
> 
> i915 already has 17 other uses of this notation and the DRM subsystem in
> general has about 50 today.  So it's not super common, but I think it
> should be okay to use.  I believe clang supports this language extension
> as well and the coding style doc doesn't say anything one way or the
> other.

I thought clang supports it for C++ rather than C, but I'm not a
clang expert, so that I might be wrong.

The fact that it is widely used is never a convincing argument
and if gcc supports it, then it does it against the standard,
both C11 and C17 (this is what puzzles me everytime I see these C
tricks offered by gcc).

Anyway, I'm not against it (nor in favour) as the ellipsis is
becoming very commonly used. My comment, by the way, did not mean
to block the patch, I just wanted to check what other people
think about.

Thanks,
Andi


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