[Intel-gfx] [PATCH v3 24/37] drm/i915: set num_fence_regs to 0 if there is no aperture

[Daniele Ceraolo Spurio]

On 8/9/19 3:26 PM, Matthew Auld wrote:
> From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> 
> We can't fence anything without aperture.

When I wrote this patch (before LMEM was in the picture) mappable 
aperture was supposed to only be missing in headless scenarios so I 
didn't consider the display case. Do we still need/use fences for direct 
access from display HW to LMEM? if so, we should drop this.

Daniele

> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Signed-off-by: Stuart Summers <stuart.summers at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gem_fence_reg.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_fence_reg.c b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
> index bcac359ec661..bb7d9321cadf 100644
> --- a/drivers/gpu/drm/i915/i915_gem_fence_reg.c
> +++ b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
> @@ -808,8 +808,10 @@ void i915_ggtt_init_fences(struct i915_ggtt *ggtt)
>   
>   	detect_bit_6_swizzle(i915);
>   
> -	if (INTEL_GEN(i915) >= 7 &&
> -	    !(IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)))
> +	if (!HAS_MAPPABLE_APERTURE(i915))
> +		num_fences = 0;
> +	else if (INTEL_GEN(i915) >= 7 &&
> +		 !(IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)))
>   		num_fences = 32;
>   	else if (INTEL_GEN(i915) >= 4 ||
>   		 IS_I945G(i915) || IS_I945GM(i915) ||
>