UAPI Changes: Cross-subsystem Changes: Core Changes: * Handle UP requests asynchronously in the DP MST helpers, fixing hotplug notifications and allowing us to implement suspend/resume reprobing * Add basic suspend/resume reprobing to the DP MST helpers * Improve locking for link address reprobing and connection status request handling in the DP MST helpers * Miscellaneous refactoring in the DP MST helpers * Add a Kconfig option to the DP MST helpers to enable tracking of gets/puts for topology references for debugging purposes Driver Changes: * nouveau: Resume hotplug interrupts earlier, so that sideband messages may be transmitted during resume and thus allow suspend/resume reprobing for DP MST to work * nouveau: Avoid grabbing runtime PM references when handling short DP pulses, so that handling sideband messages in resume codepaths with the DP MST helpers doesn't deadlock us * i915, nouveau, amdgpu, radeon: Use detect_ctx for probing MST connectors, so that we can grab the topology manager's atomic lock Note: there's some amdgpu patches that I didn't realize were pushed upstream already when creating this topic branch. When they fail to apply, you can just ignore and skip them.