path: root/drivers
diff options
authorVille Syrjälä <>2016-11-11 19:14:24 +0200
committerGreg Kroah-Hartman <>2016-11-26 09:56:56 +0100
commit899f5426eebf63e75b8e328155260883524ab344 (patch)
tree4265cb8dd2e4008270a9c52e3a32151553118397 /drivers
parentf6920e5069922618e316cc41bade636fd1186c61 (diff)
drm/i915: Assume non-DP++ port if dvo_port is HDMI and there's no AUX ch specified in the VBT
commit bc9db5ad3253c8e17969bd802c47b73e63f125ab upstream. My heuristic for detecting type 1 DVI DP++ adaptors based on the VBT port information apparently didn't survive the reality of buggy VBTs. In this particular case we have a machine with a natice HDMI port, but the VBT tells us it's a DP++ port based on its capabilities. The dvo_port information in VBT does claim that we're dealing with a HDMI port though, but we have other machines which do the same even when they actually have DP++ ports. So that piece of information alone isn't sufficient to tell the two apart. After staring at a bunch of VBTs from various machines, I have to conclude that the only other semi-reliable clue we can use is the presence of the AUX channel in the VBT. On this particular machine AUX channel is specified as zero, whereas on some of the other machines which listed the DP++ port as HDMI have a non-zero AUX channel. I've also seen VBTs which have dvo_port a DP but have a zero AUX channel. I believe those we need to treat as DP ports, so we'll limit the AUX channel check to just the cases where dvo_port is HDMI. If we encounter any more serious failures with this heuristic I think we'll have to have to throw it out entirely. But that could mean that there is a risk of type 1 DVI dongle users getting greeted by a black screen, so I'd rather not go there unless absolutely necessary. v2: Remove the duplicate PORT_A check (Daniel) Fix some typos in the commit message Cc: Daniel Otero <> Tested-by: Daniel Otero <> Fixes: d61992565bd3 ("drm/i915: Determine DP++ type 1 DVI adaptor presence based on VBT") Bugzilla: Signed-off-by: Ville Syrjälä <> Link: Reviewed-by: Daniel Vetter <> (cherry picked from commit 7a17995a3dc8613f778a9e2fd20e870f17789544) Signed-off-by: Jani Nikula <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'drivers')
2 files changed, 24 insertions, 9 deletions
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 1f8af87c6294..cf2560708e03 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1143,7 +1143,7 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
if (!child)
- aux_channel = child->raw[25];
+ aux_channel = child->common.aux_channel;
ddc_pin = child->common.ddc_pin;
is_dvi = child->common.device_type & DEVICE_TYPE_TMDS_DVI_SIGNALING;
@@ -1673,7 +1673,8 @@ bool intel_bios_is_port_edp(struct drm_i915_private *dev_priv, enum port port)
return false;
-bool intel_bios_is_port_dp_dual_mode(struct drm_i915_private *dev_priv, enum port port)
+static bool child_dev_is_dp_dual_mode(const union child_device_config *p_child,
+ enum port port)
static const struct {
u16 dp, hdmi;
@@ -1687,22 +1688,35 @@ bool intel_bios_is_port_dp_dual_mode(struct drm_i915_private *dev_priv, enum por
- int i;
if (port == PORT_A || port >= ARRAY_SIZE(port_mapping))
return false;
- if (!dev_priv->vbt.child_dev_num)
+ if ((p_child->common.device_type & DEVICE_TYPE_DP_DUAL_MODE_BITS) !=
return false;
+ if (p_child->common.dvo_port == port_mapping[port].dp)
+ return true;
+ /* Only accept a HDMI dvo_port as DP++ if it has an AUX channel */
+ if (p_child->common.dvo_port == port_mapping[port].hdmi &&
+ p_child->common.aux_channel != 0)
+ return true;
+ return false;
+bool intel_bios_is_port_dp_dual_mode(struct drm_i915_private *dev_priv,
+ enum port port)
+ int i;
for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
const union child_device_config *p_child =
- if ((p_child->common.dvo_port == port_mapping[port].dp ||
- p_child->common.dvo_port == port_mapping[port].hdmi) &&
- (p_child->common.device_type & DEVICE_TYPE_DP_DUAL_MODE_BITS) ==
+ if (child_dev_is_dp_dual_mode(p_child, port))
return true;
diff --git a/drivers/gpu/drm/i915/intel_vbt_defs.h b/drivers/gpu/drm/i915/intel_vbt_defs.h
index 68db9621f1f0..8886cab19f98 100644
--- a/drivers/gpu/drm/i915/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/intel_vbt_defs.h
@@ -280,7 +280,8 @@ struct common_child_dev_config {
u8 dp_support:1;
u8 tmds_support:1;
u8 support_reserved:5;
- u8 not_common3[12];
+ u8 aux_channel;
+ u8 not_common3[11];
u8 iboost_level;
} __packed;