diff options
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp.c | 12 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_mst.c | 40 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_mst.h | 1 |
3 files changed, 53 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 59f11af3b0a1..dc75a929d3ed 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5935,6 +5935,18 @@ intel_dp_detect(struct drm_connector *connector, else status = connector_status_disconnected; + if (status != connector_status_disconnected && + !intel_dp_mst_verify_dpcd_state(intel_dp)) + /* + * This requires retrying detection for instance to re-enable + * the MST mode that got reset via a long HPD pulse. The retry + * will happen either via the hotplug handler's retry logic, + * ensured by setting the connector here to SST/disconnected, + * or via a userspace connector probing in response to the + * hotplug uevent sent when removing the MST connectors. + */ + status = connector_status_disconnected; + if (status == connector_status_disconnected) { memset(&intel_dp->compliance, 0, sizeof(intel_dp->compliance)); memset(intel_connector->dp.dsc_dpcd, 0, sizeof(intel_connector->dp.dsc_dpcd)); diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 27ce5c3f5951..17978a1f9ab0 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -1998,3 +1998,43 @@ bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state, return false; } + +/* + * intel_dp_mst_verify_dpcd_state - verify the MST SW enabled state wrt. the DPCD + * @intel_dp: DP port object + * + * Verify if @intel_dp's MST enabled SW state matches the corresponding DPCD + * state. A long HPD pulse - not long enough to be detected as a disconnected + * state - could've reset the DPCD state, which requires tearing + * down/recreating the MST topology. + * + * Returns %true if the SW MST enabled and DPCD states match, %false + * otherwise. + */ +bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp) +{ + struct intel_display *display = to_intel_display(intel_dp); + struct intel_connector *connector = intel_dp->attached_connector; + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp); + struct intel_encoder *encoder = &dig_port->base; + int ret; + u8 val; + + if (!intel_dp->is_mst) + return true; + + ret = drm_dp_dpcd_readb(intel_dp->mst_mgr.aux, DP_MSTM_CTRL, &val); + + /* Adjust the expected register value for SST + SideBand. */ + if (ret < 0 || val != (DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC)) { + drm_dbg_kms(display->drm, + "[CONNECTOR:%d:%s][ENCODER:%d:%s] MST mode got reset, removing topology (ret=%d, ctrl=0x%02x)\n", + connector->base.base.id, connector->base.name, + encoder->base.base.id, encoder->base.name, + ret, val); + + return false; + } + + return true; +} diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h index 8ca1d599091c..9e4c7679f1c3 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.h +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h @@ -27,5 +27,6 @@ int intel_dp_mst_atomic_check_link(struct intel_atomic_state *state, struct intel_link_bw_limits *limits); bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state, struct intel_crtc *crtc); +bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp); #endif /* __INTEL_DP_MST_H__ */ |