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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 <tiwai@suse.de>
Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Adam Jackson 2012-09-18 10:58:50 -04:00 committed by Daniel Vetter
parent b091cd928d
commit 07d3dc1839
1 changed files with 34 additions and 1 deletions
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35
drivers/gpu/drm/i915/intel_dp.c
View File

@ -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;
}