If there's no downstream device, DPCD success is good enough. If
there's a hotplug-capable downstream device, count the number of
connected sinks in DP_SINK_STATUS and return success if it's non-zero.
Otherwise, probe DDC and report appropriately.
v2: Check DP_SINK_STATUS instead of something unrelated to sink status.
Tested-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Adam Jackson <ajax@xxxxxxxxxx>
---
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 098119e..813b771 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2088,11 +2088,44 @@ 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;
}
--
1.7.7.6
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