Re: [Intel-gfx] [PATCH] drm/i915/mtl: Fix MTL stolen memory GGTT mapping

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

Hi Daniele,

On Mon, Mar 27, 2023 at 06:24:30PM -0700, Daniele Ceraolo Spurio wrote:
> The PTEs expect the offset from the base of the fake LMEM region (i.e.
> the base of stolen) and not from the base of the DSM. Quoting the specs:
> "Driver will set the Device Memory bit = 1 in the PTE when pointing to a
> page in DSM and program the PTE with offset from LMEM_BAR. Device Memory
> Offset from LMEM_BAR is same as offset from BGSM."
> 
> DSM starts 8MBs from BGSM, so we set dsm_base = 8MB.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Nirmoy Das <nirmoy.das@intel.com>
> Cc: Fei Yang <fei.yang@intel.com>
> Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>

Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>

Andi