Re: [PATCH 13/16] drm/i915/bxt: Don't reprogram an already enabled DDI PHY

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

On Fri, Apr 01, 2016 at 04:02:44PM +0300, Imre Deak wrote:
> If BIOS has already programmed and enabled a PHY, don't reprogram it as
> that may interfere with the currently active outputs. A follow-up patch
> will add state verification, so we can catch any misconfiguration on
> BIOS's behalf.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>

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

> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index d16effd..8f06d6c 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1722,12 +1722,52 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder)
>  	}
>  }
>  
> +static bool broxton_phy_is_enabled(struct drm_i915_private *dev_priv,
> +				   enum dpio_phy phy)
> +{
> +	if (!(I915_READ(BXT_P_CR_GT_DISP_PWRON) & GT_DISPLAY_POWER_ON(phy)))
> +		return false;
> +
> +	if ((I915_READ(BXT_PORT_CL1CM_DW0(phy)) &
> +	     (PHY_POWER_GOOD | PHY_RESERVED)) != PHY_POWER_GOOD) {
> +		DRM_DEBUG_DRIVER("DDI PHY %d powered, but power hasn't settled\n",
> +				 phy);
> +
> +		return false;
> +	}
> +
> +	if (phy == DPIO_PHY1 &&
> +	   !(I915_READ(BXT_PORT_REF_DW3(DPIO_PHY1)) & GRC_DONE)) {
> +		DRM_DEBUG_DRIVER("DDI PHY 1 powered, but GRC isn't done\n");
> +
> +		return false;
> +	}
> +
> +	if (!(I915_READ(BXT_PHY_CTL_FAMILY(phy)) & COMMON_RESET_DIS)) {
> +		DRM_DEBUG_DRIVER("DDI PHY %d powered, but still in reset\n",
> +				 phy);
> +
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>  static void broxton_phy_init(struct drm_i915_private *dev_priv,
>  			     enum dpio_phy phy)
>  {
>  	enum port port;
>  	u32 ports, val;
>  
> +	if (broxton_phy_is_enabled(dev_priv, phy)) {
> +		DRM_DEBUG_DRIVER("DDI PHY %d already enabled, "
> +				 "won't reprogram it\n", phy);
> +
> +		return;
> +	}
> +
> +	DRM_DEBUG_DRIVER("DDI PHY %d not enabled, enabling it\n", phy);
> +
>  	val = I915_READ(BXT_P_CR_GT_DISP_PWRON);
>  	val |= GT_DISPLAY_POWER_ON(phy);
>  	I915_WRITE(BXT_P_CR_GT_DISP_PWRON, val);
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC
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