Re: [PATCH 6/7] drm/i915/psr: Use ->get_aux_send_ctl functions

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, May 18, 2016 at 06:47:15PM +0200, Daniel Vetter wrote:
> I just wanted to get rid of the rmw cycle for gen9, but this also
> fixes some bugs we haven't carried over, like using recommended
> precharge and timeout values.
> 
> Also I noticed that we don't set the fastwake sync length on skl, and
> that's used by PSR2 selective updates. Fix that.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Sonika Jindal <sonika.jindal@intel.com>
> Cc: Durgadoss R <durgadoss.r@intel.com>
> Cc: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c  |  1 +
>  drivers/gpu/drm/i915/intel_psr.c | 25 ++++---------------------
>  2 files changed, 5 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 36330026ceff..cccf9bc7c7d6 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -770,6 +770,7 @@ static uint32_t skl_get_aux_send_ctl(struct intel_dp *intel_dp,
>  	       DP_AUX_CH_CTL_TIME_OUT_1600us |
>  	       DP_AUX_CH_CTL_RECEIVE_ERROR |
>  	       (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
> +	       DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(32) |
>  	       DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 87805078c8a3..f9ce47135bb4 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -176,7 +176,6 @@ static void hsw_psr_enable_sink(struct intel_dp *intel_dp)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	uint32_t aux_clock_divider;
>  	i915_reg_t aux_ctl_reg;
> -	int precharge = 0x3;
>  	static const uint8_t aux_msg[] = {
>  		[0] = DP_AUX_NATIVE_WRITE << 4,
>  		[1] = DP_SET_POWER >> 8,
> @@ -185,6 +184,7 @@ static void hsw_psr_enable_sink(struct intel_dp *intel_dp)
>  		[4] = DP_SET_POWER_D0,
>  	};
>  	enum port port = dig_port->port;
> +	u32 aux_ctl;
>  	int i;
>  
>  	BUILD_BUG_ON(sizeof(aux_msg) > 20);
> @@ -211,26 +211,9 @@ static void hsw_psr_enable_sink(struct intel_dp *intel_dp)
>  		I915_WRITE(psr_aux_data_reg(dev_priv, port, i >> 2),
>  			   intel_dp_pack_aux(&aux_msg[i], sizeof(aux_msg) - i));
>  
> -	if (INTEL_INFO(dev)->gen >= 9) {
> -		uint32_t val;
> -
> -		val = I915_READ(aux_ctl_reg);
> -		val &= ~DP_AUX_CH_CTL_TIME_OUT_MASK;
> -		val |= DP_AUX_CH_CTL_TIME_OUT_1600us;
> -		val &= ~DP_AUX_CH_CTL_MESSAGE_SIZE_MASK;
> -		val |= (sizeof(aux_msg) << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);
> -		/* Use hardcoded data values for PSR, frame sync and GTC */
> -		val &= ~DP_AUX_CH_CTL_PSR_DATA_AUX_REG_SKL;
> -		val &= ~DP_AUX_CH_CTL_FS_DATA_AUX_REG_SKL;
> -		val &= ~DP_AUX_CH_CTL_GTC_DATA_AUX_REG_SKL;
> -		I915_WRITE(aux_ctl_reg, val);
> -	} else {
> -		I915_WRITE(aux_ctl_reg,
> -		   DP_AUX_CH_CTL_TIME_OUT_400us |
> -		   (sizeof(aux_msg) << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
> -		   (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
> -		   (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT));
> -	}
> +	aux_ctl = intel_dp->get_aux_send_ctl(intel_dp, 0, sizeof(aux_msg),
> +					     aux_clock_divider);
> +	I915_WRITE(aux_ctl_reg, aux_ctl);

The HSW/BDW EDP specific register doesn't have quite all the bits, but
looks like those bits are RO in the PSR register, so no harm in writing
1 to them.

The one difference I noticed was there's an "interrupt on error" bit
(bit 11) in the PSR register that doesn't exist in the normal register.
But we're not setting that bit here, so not a problem.

For SKL+ this makes a ton of sense to me.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

PS. perhaps someone should look into those interrupt bits a bit more?

>  }
>  
>  static void vlv_psr_enable_source(struct intel_dp *intel_dp)
> -- 
> 2.8.1
> 
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-- 
Ville Syrjälä
Intel OTC
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