[Intel-gfx] [PATCH 3/6] drm/i915: fix the watermark result selection on glk/gen10+

[Matt Roper]

On Thu, Oct 04, 2018 at 04:15:57PM -0700, Paulo Zanoni wrote:
> On these platforms we're supposed to unconditonally pick the method 2
> result instead of the minimum.

In addition to this, it looks like the calculations for method 1 and
method 2 need a slight update.  gen10/gen11 adds an extra "+1" to the
end of the method1 calculation and also to the interm_pbpl used in
various method 2 calculations.


Matt

> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 23 ++++++++++++++++-------
>  1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index cab86690a0ba..40ce99c455f3 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4672,15 +4672,24 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
>  	} else {
>  		if ((wp->cpp * cstate->base.adjusted_mode.crtc_htotal /
>  		     wp->dbuf_block_size < 1) &&
> -		     (wp->plane_bytes_per_line / wp->dbuf_block_size < 1))
> +		     (wp->plane_bytes_per_line / wp->dbuf_block_size < 1)) {
>  			selected_result = method2;
> -		else if (ddb_allocation >=
> -			 fixed16_to_u32_round_up(wp->plane_blocks_per_line))
> -			selected_result = min_fixed16(method1, method2);
> -		else if (latency >= wp->linetime_us)
> -			selected_result = min_fixed16(method1, method2);
> -		else
> +		} else if (ddb_allocation >=
> +			 fixed16_to_u32_round_up(wp->plane_blocks_per_line)) {
> +			if (INTEL_GEN(dev_priv) == 9 &&
> +			    !IS_GEMINILAKE(dev_priv))
> +				selected_result = min_fixed16(method1, method2);
> +			else
> +				selected_result = method2;
> +		} else if (latency >= wp->linetime_us) {
> +			if (INTEL_GEN(dev_priv) == 9 &&
> +			    !IS_GEMINILAKE(dev_priv))
> +				selected_result = min_fixed16(method1, method2);
> +			else
> +				selected_result = method2;
> +		} else {
>  			selected_result = method1;
> +		}
>  	}
>  
>  	res_blocks = fixed16_to_u32_round_up(selected_result) + 1;
> -- 
> 2.14.4
> 
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-- 
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795