[Intel-gfx] [PATCH v6 18/19] drm/i915/gen8: Flip the 48b switch

[Goel, Akash]

On 7/29/2015 9:54 PM, Michel Thierry wrote:
> Use 48b addresses if hw supports it (i915.enable_ppgtt=3).
>
> Note, aliasing PPGTT remains 32b only.
>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gem_gtt.c | 5 ++---
>   drivers/gpu/drm/i915/i915_params.c  | 2 +-
>   2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 0d7c7c1..a7d3c07 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -108,8 +108,7 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
>
>   	has_aliasing_ppgtt = INTEL_INFO(dev)->gen >= 6;
>   	has_full_ppgtt = INTEL_INFO(dev)->gen >= 7;
> -	has_full_64bit_ppgtt = (IS_BROADWELL(dev) ||
> -				INTEL_INFO(dev)->gen >= 9) && false; /* FIXME: 64b */
> +	has_full_64bit_ppgtt = IS_BROADWELL(dev) || INTEL_INFO(dev)->gen >= 9;
>
>   	if (intel_vgpu_active(dev))
>   		has_full_ppgtt = false; /* emulation is too hard */
> @@ -147,7 +146,7 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
>   	}
>
>   	if (INTEL_INFO(dev)->gen >= 8 && i915.enable_execlists)
> -		return 2;
> +		return has_full_64bit_ppgtt ? 3 : 2;
>   	else
>   		return has_aliasing_ppgtt ? 1 : 0;
>   }
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index 5ae4b0a..d961440 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -111,7 +111,7 @@ MODULE_PARM_DESC(enable_hangcheck,
>   module_param_named_unsafe(enable_ppgtt, i915.enable_ppgtt, int, 0400);
>   MODULE_PARM_DESC(enable_ppgtt,
>   	"Override PPGTT usage. "
> -	"(-1=auto [default], 0=disabled, 1=aliasing, 2=full)");
> +	"(-1=auto [default], 0=disabled, 1=aliasing, 2=full, 3=full_64b)");
Sorry for the late comment.
Would it be better to use '_48b' here & above, instead of '_64b', to be 
precise ?
Actually in other patches also, 48 bit has been used.

Best regards
Akash

>
>   module_param_named(enable_execlists, i915.enable_execlists, int, 0400);
>   MODULE_PARM_DESC(enable_execlists,
>