Signed-off-by: Adam Jackson <ajax at redhat.com>
---
drivers/gpu/drm/i915/intel_dp.c | 28 +++++++++++++++++++++++++++-
1 files changed, 27 insertions(+), 1 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 92939bd..9809c53 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2088,11 +2088,37 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
}
}
+/* XXX this is probably wrong for multiple downstream ports */
static enum drm_connector_status
intel_dp_detect_dpcd(struct intel_dp *intel_dp)
{
- if (intel_dp_get_dpcd(intel_dp))
+ uint8_t *dpcd = intel_dp->dpcd;
+ bool hpd;
+ uint8_t type;
+
+ if (!intel_dp_get_dpcd(intel_dp))
+ return connector_status_disconnected;
+
+ /* if there's no downstream port, we're done */
+ if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
return connector_status_connected;
+
+ /* If we're HPD-aware, SINK_COUNT changes dynamically */
+ hpd = !!(intel_dp->downstream_ports[0] & DP_DS_PORT_HPD);
+ if (hpd && (intel_dp->link_configuration[0] & DP_SINK_COUNT_MASK))
+ return connector_status_connected;
+
+ /* If no HPD, poke DDC gently */
+ if (drm_probe_ddc(&intel_dp->adapter))
+ return connector_status_connected;
+
+ /* Well we tried, say unknown for unreliable port types */
+ type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
+ if (type == DP_DS_PORT_TYPE_VGA || type == DP_DS_PORT_TYPE_NON_EDID)
+ return connector_status_unknown;
+
+ /* Anything else is out of spec, warn and ignore */
+ DRM_DEBUG_KMS("Broken DP branch device, ignoring\n");
return connector_status_disconnected;
}
--
1.7.7.6
