i2c_add_adapter() may do i2c transfers on the bus to detect supported devices. Therefore the adapter needs to be all set before adding it. This was not the case for the bit-banging fallback, resulting in an oops if the device detection GMBUS transfers timed out. Fix the issue by calling i2c_add_adapter() only after intel_gpio_setup(). LKML-Reference: <5021F00B.7000503 at ionic.de> Signed-off-by: Jani Nikula <jani.nikula at intel.com> --- drivers/gpu/drm/i915/intel_i2c.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index 1991a44..a23ba84f 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -486,9 +486,6 @@ int intel_setup_gmbus(struct drm_device *dev) bus->dev_priv = dev_priv; bus->adapter.algo = &gmbus_algorithm; - ret = i2c_add_adapter(&bus->adapter); - if (ret) - goto err; /* By default use a conservative clock rate */ bus->reg0 = port | GMBUS_RATE_100KHZ; @@ -498,6 +495,10 @@ int intel_setup_gmbus(struct drm_device *dev) bus->force_bit = true; intel_gpio_setup(bus, port); + + ret = i2c_add_adapter(&bus->adapter); + if (ret) + goto err; } intel_i2c_reset(dev_priv->dev); -- 1.7.9.5
