drm/i915: Apply the PPS register unlock workaround more consistently

Atm, we apply this workaround somewhat inconsistently at the following
points: driver loading, LVDS init, eDP PPS init, system resume. As this
workaround also affects registers other than PPS (timing, PLL) a more
consistent way is to apply it early after the PPS HW context is known to
be lost: driver loading, system resume and on VLV/CHV/BXT when turning
on power domains.

This is needed by the next patch that removes saving/restoring of the
PP_CONTROL register.

This also removes the incorrect programming of the workaround on HSW+
PCH platforms which don't have the register locking mechanism.

v2: (Ville)
- Don't apply the workaround on BXT.
- Simplify platform checks using HAS_DDI().
v3:
- Move the call of intel_pps_unlock_regs_wa() to the more
  logical vlv_display_power_well_init() (also fixing CHV) (Ville).

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470827254-21954-5-git-send-email-imre.deak@intel.com

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 1c603bbe5784..d659d6f5b8d3 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -592,6 +592,8 @@ void bxt_disable_dc9(struct drm_i915_private *dev_priv)
 	DRM_DEBUG_KMS("Disabling DC9\n");
 
 	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
+
+	intel_pps_unlock_regs_wa(dev_priv);
 }
 
 static void assert_csr_loaded(struct drm_i915_private *dev_priv)
@@ -1121,6 +1123,8 @@ static void vlv_display_power_well_init(struct drm_i915_private *dev_priv)
 	}
 
 	i915_redisable_vga_power_on(&dev_priv->drm);
+
+	intel_pps_unlock_regs_wa(dev_priv);
 }
 
 static void vlv_display_power_well_deinit(struct drm_i915_private *dev_priv)