[Intel-gfx] [PATCH CI] drm/i915/psr: Share the computation of idle frames

[Matt Roper]

On Mon, Jan 13, 2020 at 01:46:03PM -0800, José Roberto de Souza wrote:
> Both activate functions and the dc3co disable function were doing the
> same thing, so better move to a function and share.
> Also while at it adding a WARN_ON to catch invalid values.
> 
> Cc: Anshuman Gupta <anshuman.gupta at intel.com>
> Cc: Imre Deak <imre.deak at intel.com>
> Reviewed-by: Anshuman Gupta <anshuman.gupta at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 43 +++++++++++-------------
>  1 file changed, 19 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 89c9cf5f38d2..bd713ca8d5fc 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -454,22 +454,29 @@ static u32 intel_psr1_get_tp_time(struct intel_dp *intel_dp)
>  	return val;
>  }
>  
> -static void hsw_activate_psr1(struct intel_dp *intel_dp)
> +static u8 psr_compute_idle_frames(struct intel_dp *intel_dp)
>  {
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> -	u32 max_sleep_time = 0x1f;
> -	u32 val = EDP_PSR_ENABLE;
> +	int idle_frames;
>  
>  	/* Let's use 6 as the minimum to cover all known cases including the
>  	 * off-by-one issue that HW has in some cases.
>  	 */
> -	int idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
> -
> -	/* sink_sync_latency of 8 means source has to wait for more than 8
> -	 * frames, we'll go with 9 frames for now
> -	 */
> +	idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
>  	idle_frames = max(idle_frames, dev_priv->psr.sink_sync_latency + 1);
> -	val |= idle_frames << EDP_PSR_IDLE_FRAME_SHIFT;
> +
> +	WARN_ON(idle_frames > 0xf);

Should we clamp the value if the VBT gives us something that's too large
to fit in the register bits?  Seems like

        if (WARN_ON(idle_frames > 0xf))
                idle_frames = 0xf;

might be better than letting the value spill over into unrelated
parts of the register?

Either way, the changes here maintain the code's current logic, so

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>


Matt

> +
> +	return idle_frames;
> +}
> +
> +static void hsw_activate_psr1(struct intel_dp *intel_dp)
> +{
> +	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> +	u32 max_sleep_time = 0x1f;
> +	u32 val = EDP_PSR_ENABLE;
> +
> +	val |= psr_compute_idle_frames(intel_dp) << EDP_PSR_IDLE_FRAME_SHIFT;
>  
>  	val |= max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT;
>  	if (IS_HASWELL(dev_priv))
> @@ -493,13 +500,7 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>  	u32 val;
>  
> -	/* Let's use 6 as the minimum to cover all known cases including the
> -	 * off-by-one issue that HW has in some cases.
> -	 */
> -	int idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
> -
> -	idle_frames = max(idle_frames, dev_priv->psr.sink_sync_latency + 1);
> -	val = idle_frames << EDP_PSR2_IDLE_FRAME_SHIFT;
> +	val = psr_compute_idle_frames(intel_dp) << EDP_PSR2_IDLE_FRAME_SHIFT;
>  
>  	val |= EDP_PSR2_ENABLE | EDP_SU_TRACK_ENABLE;
>  	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
> @@ -566,16 +567,10 @@ static void tgl_psr2_enable_dc3co(struct drm_i915_private *dev_priv)
>  
>  static void tgl_psr2_disable_dc3co(struct drm_i915_private *dev_priv)
>  {
> -	int idle_frames;
> +	struct intel_dp *intel_dp = dev_priv->psr.dp;
>  
>  	intel_display_power_set_target_dc_state(dev_priv, DC_STATE_EN_UPTO_DC6);
> -	/*
> -	 * Restore PSR2 idle frame let's use 6 as the minimum to cover all known
> -	 * cases including the off-by-one issue that HW has in some cases.
> -	 */
> -	idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
> -	idle_frames = max(idle_frames, dev_priv->psr.sink_sync_latency + 1);
> -	psr2_program_idle_frames(dev_priv, idle_frames);
> +	psr2_program_idle_frames(dev_priv, psr_compute_idle_frames(intel_dp));
>  }
>  
>  static void tgl_dc5_idle_thread(struct work_struct *work)
> -- 
> 2.24.1
> 
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-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795