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

[Lucas De Marchi]

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

clang also supports it and can build the kernel (or a great portion of
it).

Lucas De Marchi