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>

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index d97e6cb..27e63ab 100644 (file)
--- 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