Re: [PATCH v4 03/18] drm/i915/gen8: Add PML4 structure

Chris Wilson
2015-07-11T20:02:15Z

On Tue, Jul 07, 2015 at 04:14:48PM +0100, Michel Thierry wrote:
> Introduces the Page Map Level 4 (PML4), ie. the new top level structure
> of the page tables.
>
> To facilitate testing, 48b mode will be available on Broadwell and
> GEN9+, when i915.enable_ppgtt = 3.
>
> Cc: Akash Goel <akash.goel@intel.com>
> Signed-off-by: Michel Thierry <michel.thierry@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 7 ++++++-
> drivers/gpu/drm/i915/i915_gem_gtt.c | 40 ++++++++++++++++++++++++-------------
> drivers/gpu/drm/i915/i915_gem_gtt.h | 35 ++++++++++++++++++++++++--------
> 3 files changed, 59 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 464b28d..de3a5d1 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2497,7 +2497,12 @@ struct drm_i915_cmd_table {
> #define HAS_HW_CONTEXTS(dev) (INTEL_INFO(dev)->gen >= 6)
> #define HAS_LOGICAL_RING_CONTEXTS(dev) (INTEL_INFO(dev)->gen >= 8)
> #define USES_PPGTT(dev) (i915.enable_ppgtt)
> -#define USES_FULL_PPGTT(dev) (i915.enable_ppgtt == 2)
> +#define USES_FULL_PPGTT(dev) (i915.enable_ppgtt >= 2)
> +#ifdef CONFIG_X86_64
> +# define USES_FULL_48BIT_PPGTT(dev) (i915.enable_ppgtt == 3)
> +#else
> +# define USES_FULL_48BIT_PPGTT(dev) false
> +#endif

This requires an explanation.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre