drm/i915: don't save/restore PCH_LVDS on LPT

Because the register does not exist on LPT. The interesting fact is
that reading/writing PCH_LVDS on LPT does *not* give us "unclaimed
register" messages, but the register value is always 0.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index c1e02b040a34..41f0fdecfbdc 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -209,7 +209,8 @@ static void i915_save_display(struct drm_device *dev)
                 dev_priv->regfile.saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_PCH_CTL2);
                 dev_priv->regfile.saveBLC_CPU_PWM_CTL = I915_READ(BLC_PWM_CPU_CTL);
                 dev_priv->regfile.saveBLC_CPU_PWM_CTL2 = I915_READ(BLC_PWM_CPU_CTL2);
-                dev_priv->regfile.saveLVDS = I915_READ(PCH_LVDS);
+                if (HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev))
+                        dev_priv->regfile.saveLVDS = I915_READ(PCH_LVDS);
         } else {
                 dev_priv->regfile.savePP_CONTROL = I915_READ(PP_CONTROL);
                 dev_priv->regfile.savePFIT_PGM_RATIOS = I915_READ(PFIT_PGM_RATIOS);
@@ -271,9 +272,9 @@ static void i915_restore_display(struct drm_device *dev)
         if (drm_core_check_feature(dev, DRIVER_MODESET))
                 mask = ~LVDS_PORT_EN;
 
-        if (HAS_PCH_SPLIT(dev)) {
+        if (HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev))
                 I915_WRITE(PCH_LVDS, dev_priv->regfile.saveLVDS & mask);
-        } else if (IS_MOBILE(dev) && !IS_I830(dev))
+        else if (INTEL_INFO(dev)->gen <= 4 && IS_MOBILE(dev) && !IS_I830(dev))
                 I915_WRITE(LVDS, dev_priv->regfile.saveLVDS & mask);
 
         if (!IS_I830(dev) && !IS_845G(dev) && !HAS_PCH_SPLIT(dev))