From 07d3dc18396790d9d394f4f0717a91b3a845c758 Mon Sep 17 00:00:00 2001 From: Adam Jackson Date: Tue, 18 Sep 2012 10:58:50 -0400 Subject: [PATCH] drm/i915/dp: Be smarter about connection sense for branch devices 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 Signed-off-by: Adam Jackson Reviewed-by: Jani Nikula Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dp.c | 35 ++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) 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; } -- 2.20.1