1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define LOG_TAG "hwc-uevent-listener" 18 19 #include "UEventListener.h" 20 21 #include <cerrno> 22 23 #include "utils/log.h" 24 25 /* Originally defined in system/core/libsystem/include/system/graphics.h as 26 * #define HAL_PRIORITY_URGENT_DISPLAY (-8)*/ 27 constexpr int kHalPriorityUrgentDisplay = -8; 28 29 namespace android { 30 UEventListener()31UEventListener::UEventListener() 32 : Worker("uevent-listener", kHalPriorityUrgentDisplay){}; 33 Init()34int UEventListener::Init() { 35 uevent_ = UEvent::CreateInstance(); 36 if (!uevent_) { 37 return -ENODEV; 38 } 39 40 return InitWorker(); 41 } 42 Routine()43void UEventListener::Routine() { 44 while (true) { 45 auto uevent_str = uevent_->ReadNext(); 46 47 if (!hotplug_handler_ || !uevent_str) 48 continue; 49 50 bool drm_event = uevent_str->find("DEVTYPE=drm_minor") != std::string::npos; 51 bool hotplug_event = uevent_str->find("HOTPLUG=1") != std::string::npos; 52 53 if (drm_event && hotplug_event) { 54 constexpr useconds_t kDelayAfterUeventUs = 200000; 55 /* We need some delay to ensure DrmConnector::UpdateModes() will query 56 * correct modes list, otherwise at least RPI4 board may report 0 modes */ 57 usleep(kDelayAfterUeventUs); 58 hotplug_handler_(); 59 } 60 } 61 } 62 } // namespace android 63