drm/i915/sdvo: Only use the SDVO pin if it is in the valid range

BIOSes. Can't live without them (apparently), definitely can't live with
them.

Reported-by: Ben Gamari <bgamari@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=24312
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index d97e6cb52d34..27e63abf2a73 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1908,9 +1908,12 @@ intel_sdvo_select_i2c_bus(struct drm_i915_private *dev_priv,
                 speed = mapping->i2c_speed;
         }
 
-        sdvo->i2c = &dev_priv->gmbus[pin].adapter;
-        intel_gmbus_set_speed(sdvo->i2c, speed);
-        intel_gmbus_force_bit(sdvo->i2c, true);
+        if (pin < GMBUS_NUM_PORTS) {
+                sdvo->i2c = &dev_priv->gmbus[pin].adapter;
+                intel_gmbus_set_speed(sdvo->i2c, speed);
+                intel_gmbus_force_bit(sdvo->i2c, true);
+        } else
+                sdvo->i2c = &dev_priv->gmbus[GMBUS_PORT_DPB].adapter;
 }
 
 static bool