On Tue, Sep 20, 2022 at 06:57:46PM +0200, Andi Shyti wrote:
> Hi Aravind,
>
> > +static int get_mtl_gms_size(struct intel_uncore *uncore)
> > +{
> > + u16 ggc, gms;
> > +
> > + ggc = intel_uncore_read16(uncore, _MMIO(0x108040));
> > +
> > + /* check GGMS, should be fixed 0x3 (8MB) */
> > + if ((ggc & 0xc0) != 0xc0)
> > + return -EIO;
> > +
> > + /* return valid GMS value, -EIO if invalid */
> > + gms = ggc >> 8;
> > + 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.
Matt
>
> Andi
>
> > + return (gms - 0xf0 + 1) * 4;
> > + default:
> > + return -EIO;
> > + }
> > +}
--
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
