Re: [PATCH 4/5] drm/i915/icl: Skip init for an already enabled combo PHY

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Nov 02, 2018 at 08:07:05PM +0200, Imre Deak wrote:
> Bspec says we should skip the initialization of combo PHYs that are
> already initialized. We'll need to reinit the PHYs more frequently
> when exiting from DC6 (after the next patch), so let's make sure the
> uninit sequence complies with the spec. For safety skip the init only if
> all the PHY register fields have their expected values.
> 
> Bspec: 21257
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_combo_phy.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_combo_phy.c b/drivers/gpu/drm/i915/intel_combo_phy.c
> index 1522e2a25390..7b911702f834 100644
> --- a/drivers/gpu/drm/i915/intel_combo_phy.c
> +++ b/drivers/gpu/drm/i915/intel_combo_phy.c
> @@ -220,6 +220,12 @@ void icl_combo_phys_init(struct drm_i915_private *dev_priv)
>  	for (port = PORT_A; port <= PORT_B; port++) {
>  		u32 val;
>  
> +		if (icl_combo_phy_verify_state(dev_priv, port)) {
> +			DRM_DEBUG_DRIVER("Port-%c combo PHY already enabled, won't reprogram it.\n",
> +					 port_name(port));

Note since I didn't rv-b the previous patch:
I have checked the previous patch that introduces this and it is indeed correct:

"If PORT_COMP_DW0 Comp Init == 1b, skip the rest of this sequence since it is already initialized"

so,

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> +			continue;
> +		}
> +
>  		val = I915_READ(ICL_PHY_MISC(port));
>  		val &= ~ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
>  		I915_WRITE(ICL_PHY_MISC(port), val);
> -- 
> 2.13.2
> 
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