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Commit 428d2e82 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/lvds: Probe DDC on creation 

Try to validate the panel's connection by writing to address 0xA0.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18072


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 29e1316a

drivers/gpu/drm/i915/intel_lvds.c

+21 −0
Original line number Diff line number Diff line
@@ -810,6 +810,22 @@ static bool lvds_is_present_in_vbt(struct drm_device *dev) 
	return false;

}



static bool intel_lvds_ddc_probe(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	u8 buf = 0;

	struct i2c_msg msgs[] = {

		{

			.addr = 0xA0,

			.flags = 0,

			.len = 1,

			.buf = &buf,

		},

	};

	struct i2c_adapter *i2c = &dev_priv->gmbus[GMBUS_PORT_PANEL].adapter;

	return i2c_transfer(i2c, msgs, 1) == 1;

}



/**

 * intel_lvds_init - setup LVDS connectors on this device

 * @dev: drm device
@@ -849,6 +865,11 @@ void intel_lvds_init(struct drm_device *dev) 
		gpio = PCH_GPIOC;

	}



	if (!intel_lvds_ddc_probe(dev)) {

		DRM_DEBUG_KMS("LVDS did not respond to DDC probe\n");

		return;

	}



	intel_lvds = kzalloc(sizeof(struct intel_lvds), GFP_KERNEL);

	if (!intel_lvds) {

		return;