[Intel-gfx] [PATCH v2 7/8] drm/i915/skl: Enable Per context Preemption granularity control

[Nick Hoath]

On 21/01/2016 14:00, Arun Siluvery wrote:
> Per context preemption granularity control is only available from SKL:E0+
>
> Cc: Dave Gordon <david.s.gordon at intel.com>
> Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>

Reviewed-by: Nick Hoath <nicholas.hoath at intel.com>

> ---
>   drivers/gpu/drm/i915/i915_reg.h         |  3 +++
>   drivers/gpu/drm/i915/intel_ringbuffer.c | 10 ++++++++++
>   2 files changed, 13 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c51e7e9..65e32a3 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5995,6 +5995,9 @@ enum skl_disp_power_wells {
>   #define SKL_DFSM_CDCLK_LIMIT_450	(2 << 23)
>   #define SKL_DFSM_CDCLK_LIMIT_337_5	(3 << 23)
>
> +#define GEN7_FF_SLICE_CS_CHICKEN1	_MMIO(0x20e0)
> +#define   GEN9_FFSC_PERCTX_PREEMPT_CTRL	(1<<14)
> +
>   #define FF_SLICE_CS_CHICKEN2			_MMIO(0x20e4)
>   #define  GEN9_TSG_BARRIER_ACK_DISABLE		(1<<8)
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index ce64519..e91fb70 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1044,6 +1044,16 @@ static int skl_init_workarounds(struct intel_engine_cs *ring)
>   	if (ret)
>   		return ret;
>
> +	/*
> +	 * Actual WA is to disable percontext preemption granularity control
> +	 * until D0 which is the default case so this is equivalent to
> +	 * !WaDisablePerCtxtPreemptionGranularityControl:skl
> +	 */
> +	if (IS_SKL_REVID(dev, SKL_REVID_E0, REVID_FOREVER)) {
> +		I915_WRITE(GEN7_FF_SLICE_CS_CHICKEN1,
> +			   _MASKED_BIT_ENABLE(GEN9_FFSC_PERCTX_PREEMPT_CTRL));
> +	}
> +
>   	if (IS_SKL_REVID(dev, 0, SKL_REVID_D0)) {
>   		/* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
>   		I915_WRITE(FF_SLICE_CS_CHICKEN2,
>