[Intel-gfx] [PATCH 2/2] drm/i915: Skip CHV PHY asserts until PHY has been fully reset

[Deepak]

On Tuesday 08 September 2015 08:35 PM, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> The BIOS can leave the CHV display PHY in some odd state where
> some of the LDOs/lanes won't power down fully when unused. This
> will trigger a host of asserts that were added in:
> 30142273a3e83936fd7b45aa5339311a9295ca51 drm/i915: Add CHV PHY LDO power sanity checks
> 6669e39f95b5530ca8cb9137703ceb5e83e5d648 drm/i915: Add some CHV DPIO lane power state asserts
>
> To avoid that, skip the asserts until the PHY power well has been
> disabled at least once. That will fully reset the PHY, and once
> brought back up, the dynamic power down features will work correctly.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h         |  3 +++
>   drivers/gpu/drm/i915/intel_runtime_pm.c | 46 ++++++++++++++++++++++++++++++++-
>   2 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 503dff5..cf1880e 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1956,6 +1956,9 @@ struct drm_i915_private {
>   
>   	bool edp_low_vswing;
>   
> +	/* perform PHY state sanity checks? */
> +	bool chv_phy_assert[2];
> +
>   	/*
>   	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
>   	 * will be rejected. Instead look for a better place.
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 3f682a1..a0a2e6d 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -987,8 +987,29 @@ static void assert_chv_phy_status(struct drm_i915_private *dev_priv)
>   		lookup_power_well(dev_priv, PUNIT_POWER_WELL_DPIO_CMN_D);
>   	u32 phy_control = dev_priv->chv_phy_control;
>   	u32 phy_status = 0;
> +	u32 phy_status_mask = 0xffffffff;
>   	u32 tmp;
>   
> +	/*
> +	 * The BIOS can leave the PHY is some weird state
> +	 * where it doesn't fully power down some parts.
> +	 * Disable the asserts until the PHY has been fully
> +	 * reset (ie. the power well has been disabled at
> +	 * least once).
> +	 */
> +	if (!dev_priv->chv_phy_assert[DPIO_PHY0])
> +		phy_status_mask &= ~(PHY_STATUS_CMN_LDO(DPIO_PHY0, DPIO_CH0) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY0, DPIO_CH0, 0) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY0, DPIO_CH0, 1) |
> +				     PHY_STATUS_CMN_LDO(DPIO_PHY0, DPIO_CH1) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY0, DPIO_CH1, 0) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY0, DPIO_CH1, 1));
> +
> +	if (!dev_priv->chv_phy_assert[DPIO_PHY1])
> +		phy_status_mask &= ~(PHY_STATUS_CMN_LDO(DPIO_PHY1, DPIO_CH0) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY1, DPIO_CH0, 0) |
> +				     PHY_STATUS_SPLINE_LDO(DPIO_PHY1, DPIO_CH0, 1));
> +
>   	if (cmn_bc->ops->is_enabled(dev_priv, cmn_bc)) {
>   		phy_status |= PHY_POWERGOOD(DPIO_PHY0);
>   
> @@ -1049,11 +1070,13 @@ static void assert_chv_phy_status(struct drm_i915_private *dev_priv)
>   			phy_status |= PHY_STATUS_SPLINE_LDO(DPIO_PHY1, DPIO_CH0, 1);
>   	}
>   
> +	phy_status &= phy_status_mask;
> +
>   	/*
>   	 * The PHY may be busy with some initial calibration and whatnot,
>   	 * so the power state can take a while to actually change.
>   	 */
> -	if (wait_for((tmp = I915_READ(DISPLAY_PHY_STATUS)) == phy_status, 10))
> +	if (wait_for((tmp = I915_READ(DISPLAY_PHY_STATUS) & phy_status_mask) == phy_status, 10))
>   		WARN(phy_status != tmp,
>   		     "Unexpected PHY_STATUS 0x%08x, expected 0x%08x (PHY_CONTROL=0x%08x)\n",
>   		     tmp, phy_status, dev_priv->chv_phy_control);
> @@ -1146,6 +1169,9 @@ static void chv_dpio_cmn_power_well_disable(struct drm_i915_private *dev_priv,
>   	DRM_DEBUG_KMS("Disabled DPIO PHY%d (PHY_CONTROL=0x%08x)\n",
>   		      phy, dev_priv->chv_phy_control);
>   
> +	/* PHY is fully reset now, so we can enable the PHY state asserts */
> +	dev_priv->chv_phy_assert[phy] = true;
> +
>   	assert_chv_phy_status(dev_priv);
>   }
>   
> @@ -1155,6 +1181,16 @@ static void assert_chv_phy_powergate(struct drm_i915_private *dev_priv, enum dpi
>   	enum pipe pipe = phy == DPIO_PHY0 ? PIPE_A : PIPE_C;
>   	u32 reg, val, expected, actual;
>   
> +	/*
> +	 * The BIOS can leave the PHY is some weird state
> +	 * where it doesn't fully power down some parts.
> +	 * Disable the asserts until the PHY has been fully
> +	 * reset (ie. the power well has been disabled at
> +	 * least once).
> +	 */
> +	if (!dev_priv->chv_phy_assert[phy])
> +		return;
> +
>   	if (ch == DPIO_CH0)
>   		reg = _CHV_CMN_DW0_CH0;
>   	else
> @@ -1911,6 +1947,10 @@ static void chv_phy_control_init(struct drm_i915_private *dev_priv)
>   			PHY_CH_POWER_DOWN_OVRD(mask, DPIO_PHY0, DPIO_CH1);
>   
>   		dev_priv->chv_phy_control |= PHY_COM_LANE_RESET_DEASSERT(DPIO_PHY0);
> +
> +		dev_priv->chv_phy_assert[DPIO_PHY0] = false;
> +	} else {
> +		dev_priv->chv_phy_assert[DPIO_PHY0] = true;
>   	}
>   
>   	if (cmn_d->ops->is_enabled(dev_priv, cmn_d)) {
> @@ -1929,6 +1969,10 @@ static void chv_phy_control_init(struct drm_i915_private *dev_priv)
>   			PHY_CH_POWER_DOWN_OVRD(mask, DPIO_PHY1, DPIO_CH0);
>   
>   		dev_priv->chv_phy_control |= PHY_COM_LANE_RESET_DEASSERT(DPIO_PHY1);
> +
> +		dev_priv->chv_phy_assert[DPIO_PHY1] = false;
> +	} else {
> +		dev_priv->chv_phy_assert[DPIO_PHY1] = true;
>   	}
>   
>   	I915_WRITE(DISPLAY_PHY_CONTROL, dev_priv->chv_phy_control);

Change looks fine.
Reviewed-by: Deepak S<deepak.s at linux.intel.com>