diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 42bdca47c5d6..4f2a38181491 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -2083,11 +2083,44 @@ 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) { + uint8_t sink_count; + if (!intel_dp_aux_native_read_retry(intel_dp, DP_SINK_COUNT, + &sink_count, 1)) + return connector_status_unknown; + sink_count &= DP_SINK_COUNT_MASK; + return sink_count ? connector_status_connected + : connector_status_disconnected; + } + + /* 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; } |
