From 428d2e828c0a68206e5158a42451487601dc9194 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 23 Sep 2010 11:16:49 +0100 Subject: [PATCH] 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: Chris Wilson --- drivers/gpu/drm/i915/intel_lvds.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 2bcea800..e1f6e05 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -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; -- 2.7.4