Commit 1b2db4ce authored by Alan Cox's avatar Alan Cox Committed by Dave Airlie
Browse files

gma500: panel presence check

Introduce a panel presence check for Cedartrail. Non netbook devices don't
necessarily have a panel attached.
Signed-off-by: default avatarAlan Cox <>
Signed-off-by: default avatarDave Airlie <>
parent 1fb28e9e
......@@ -556,6 +556,56 @@ const struct drm_encoder_funcs cdv_intel_lvds_enc_funcs = {
.destroy = cdv_intel_lvds_enc_destroy,
* Enumerate the child dev array parsed from VBT to check whether
* the LVDS is present.
* If it is present, return 1.
* If it is not present, return false.
* If no child dev is parsed from VBT, it assumes that the LVDS is present.
static bool lvds_is_present_in_vbt(struct drm_device *dev,
u8 *i2c_pin)
struct drm_psb_private *dev_priv = dev->dev_private;
int i;
if (!dev_priv->child_dev_num)
return true;
for (i = 0; i < dev_priv->child_dev_num; i++) {
struct child_device_config *child = dev_priv->child_dev + i;
/* If the device type is not LFP, continue.
* We have to check both the new identifiers as well as the
* old for compatibility with some BIOSes.
if (child->device_type != DEVICE_TYPE_INT_LFP &&
child->device_type != DEVICE_TYPE_LFP)
if (child->i2c_pin)
*i2c_pin = child->i2c_pin;
/* However, we cannot trust the BIOS writers to populate
* the VBT correctly. Since LVDS requires additional
* information from AIM blocks, a non-zero addin offset is
* a good indicator that the LVDS is actually present.
if (child->addin_offset)
return true;
/* But even then some BIOS writers perform some black magic
* and instantiate the device without reference to any
* additional data. Trust that if the VBT was written into
* the OpRegion then they have validated the LVDS's existence.
if (dev_priv->opregion.vbt)
return true;
return false;
* cdv_intel_lvds_init - setup LVDS connectors on this device
* @dev: drm device
......@@ -576,6 +626,13 @@ void cdv_intel_lvds_init(struct drm_device *dev,
struct drm_psb_private *dev_priv = dev->dev_private;
u32 lvds;
int pipe;
u8 pin;
if (!lvds_is_present_in_vbt(dev, &pin)) {
DRM_DEBUG_KMS("LVDS is not present in VBT\n");
psb_intel_encoder = kzalloc(sizeof(struct psb_intel_encoder),
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