[Intel-gfx] [PATCH] drm/i915/cnl: WaDisableI2mCycleOnWRPort

[Mika Kuoppala]

Rodrigo Vivi <rodrigo.vivi at intel.com> writes:

> On CNL B0 stepping GAM is not able to detect some deadlock
> condition and then rise the rise the gam_coh_flush.
>
> WA database and spec both mentions to set 4AB8[24]=1 as
> workaround. Alghouth register offset 0x4AB8 is not
s/Alghouth/Although

> documented for any platform.
>

References: HSD#1945815, BSID#1112

> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h        | 1 +
>  drivers/gpu/drm/i915/intel_engine_cs.c | 5 +++++
>  2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index e2908ae34004..bbacdac5c794 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2373,6 +2373,7 @@ enum i915_power_well_id {
>  
>  #define GAMT_CHKN_BIT_REG	_MMIO(0x4ab8)
>  #define   GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING	(1<<28)
> +#define   GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT	(1<<24)
>  
>  #if 0
>  #define PRB0_TAIL	_MMIO(0x2030)
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index a6ac9d0a4156..f087eb6b0134 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -1070,6 +1070,11 @@ static int cnl_init_workarounds(struct intel_engine_cs *engine)
>  	struct drm_i915_private *dev_priv = engine->i915;
>  	int ret;
>  
> +	/* WaDisableI2mCycleOnWRPort: cnl (pre-prod) */
> +	if (IS_CNL_REVID(dev_priv, CNL_REVID_B0, CNL_REVID_B0))
> +		WA_SET_BIT(GAMT_CHKN_BIT_REG,
> +			   GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT);
> +
>  	/* WaForceContextSaveRestoreNonCoherent:cnl */
>  	WA_SET_BIT_MASKED(CNL_HDC_CHICKEN0,
>  			  HDC_FORCE_CONTEXT_SAVE_RESTORE_NON_COHERENT);
> -- 
> 2.13.2
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx