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

[Andi Shyti <andi.shyti@linux.intel.com>]

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?

Andi

> +		return (gms - 0xf0 + 1) * 4;
> +	default:
> +		return -EIO;
> +	}
> +}