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gma500: panel presence check 

Introduce a panel presence check for Cedartrail. Non netbook devices don't
necessarily have a panel attached.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Alan Cox 2012-04-25 14:37:27 +01:00 committed by Dave Airlie
parent 1fb28e9e73
commit 1b2db4cee5
1 changed files with 57 additions and 0 deletions
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57
drivers/gpu/drm/gma500/cdv_intel_lvds.c
View File

@ -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)
continue;
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;
pin = GMBUS_PORT_PANEL;
if (!lvds_is_present_in_vbt(dev, &pin)) {
DRM_DEBUG_KMS("LVDS is not present in VBT\n");
return;
}
psb_intel_encoder = kzalloc(sizeof(struct psb_intel_encoder),
GFP_KERNEL);