From 1b2db4cee5433e089533f81fea6721c1b653703c Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 25 Apr 2012 14:37:27 +0100 Subject: [PATCH] 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 Signed-off-by: Dave Airlie --- drivers/gpu/drm/gma500/cdv_intel_lvds.c | 57 +++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/drivers/gpu/drm/gma500/cdv_intel_lvds.c b/drivers/gpu/drm/gma500/cdv_intel_lvds.c index 8359c1a3f45..c87b179eadf 100644 --- a/drivers/gpu/drm/gma500/cdv_intel_lvds.c +++ b/drivers/gpu/drm/gma500/cdv_intel_lvds.c @@ -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); -- 2.41.0