drm/i915: Add a module option to override the use of SSC

In order to workaround the issue with LVDS not working on the Lenovo
U160 apparently due to using the wrong SSC frequency, add an option to
disable SSC.

Suggested-by: Lukács, Árpád <lukacs.arpad@gmail.com>
Bugzillla: https://bugs.freedesktop.org/show_bug.cgi?id=32748
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

1 files changed, 6 insertions, 11 deletions

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index b0b1200ed650..0b44956c336b 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -264,17 +264,12 @@ parse_general_features(struct drm_i915_private *dev_priv,
                 dev_priv->int_crt_support = general->int_crt_support;
                 dev_priv->lvds_use_ssc = general->enable_ssc;
 
-                if (dev_priv->lvds_use_ssc) {
-                        if (IS_I85X(dev))
-                                dev_priv->lvds_ssc_freq =
-                                        general->ssc_freq ? 66 : 48;
-                        else if (IS_GEN5(dev) || IS_GEN6(dev))
-                                dev_priv->lvds_ssc_freq =
-                                        general->ssc_freq ? 100 : 120;
-                        else
-                                dev_priv->lvds_ssc_freq =
-                                        general->ssc_freq ? 100 : 96;
-                }
+                if (IS_I85X(dev))
+                        dev_priv->lvds_ssc_freq = general->ssc_freq ? 66 : 48;
+                else if (IS_GEN5(dev) || IS_GEN6(dev))
+                        dev_priv->lvds_ssc_freq = general->ssc_freq ? 100 : 120;
+                else
+                        dev_priv->lvds_ssc_freq = general->ssc_freq ? 100 : 96;
         }
 }