adb: libusb: switch to hotplug for device detection.
Switch from polling in a loop to using libusb's hotplug API to detect
when devices arrive and leave. Use this to remove devices that were
inaccessible when they're unplugged.
Bug: http://b/38170349
Test: plugged in device
Change-Id: Id157412eb46834debecb0cd45b47b1ced50c2274
diff --git a/adb/client/usb_libusb.cpp b/adb/client/usb_libusb.cpp
index 18a8ff2..0068e08 100644
--- a/adb/client/usb_libusb.cpp
+++ b/adb/client/usb_libusb.cpp
@@ -151,10 +151,7 @@
static auto& usb_handles = *new std::unordered_map<std::string, std::unique_ptr<usb_handle>>();
static auto& usb_handles_mutex = *new std::mutex();
-static std::thread* device_poll_thread = nullptr;
-static bool terminate_device_poll_thread = false;
-static auto& device_poll_mutex = *new std::mutex();
-static auto& device_poll_cv = *new std::condition_variable();
+static libusb_hotplug_callback_handle hotplug_handle;
static std::string get_device_address(libusb_device* device) {
return StringPrintf("usb:%d:%d", libusb_get_bus_number(device),
@@ -375,29 +372,31 @@
LOG(INFO) << "registered new usb device '" << device_serial << "'";
}
-static void poll_for_devices() {
- libusb_device** list;
- adb_thread_setname("device poll");
- while (true) {
- const ssize_t device_count = libusb_get_device_list(nullptr, &list);
+static void remove_device(libusb_device* device) {
+ std::string device_address = get_device_address(device);
- LOG(VERBOSE) << "found " << device_count << " attached devices";
-
- for (ssize_t i = 0; i < device_count; ++i) {
- process_device(list[i]);
+ LOG(INFO) << "device disconnected: " << device_address;
+ std::unique_lock<std::mutex> lock(usb_handles_mutex);
+ auto it = usb_handles.find(device_address);
+ if (it != usb_handles.end()) {
+ if (!it->second->device_handle) {
+ // If the handle is null, we were never able to open the device.
+ unregister_usb_transport(it->second.get());
}
-
- libusb_free_device_list(list, 1);
-
- adb_notify_device_scan_complete();
-
- std::unique_lock<std::mutex> lock(device_poll_mutex);
- if (device_poll_cv.wait_for(lock, 500ms, []() { return terminate_device_poll_thread; })) {
- return;
- }
+ usb_handles.erase(it);
}
}
+static int hotplug_callback(libusb_context*, libusb_device* device, libusb_hotplug_event event,
+ void*) {
+ if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
+ process_device(device);
+ } else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) {
+ remove_device(device);
+ }
+ return 0;
+}
+
void usb_init() {
LOG(DEBUG) << "initializing libusb...";
int rc = libusb_init(nullptr);
@@ -405,6 +404,19 @@
LOG(FATAL) << "failed to initialize libusb: " << libusb_error_name(rc);
}
+ // Register the hotplug callback.
+ rc = libusb_hotplug_register_callback(
+ nullptr, static_cast<libusb_hotplug_event>(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
+ LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
+ LIBUSB_HOTPLUG_ENUMERATE, LIBUSB_HOTPLUG_MATCH_ANY, LIBUSB_HOTPLUG_MATCH_ANY,
+ LIBUSB_CLASS_PER_INTERFACE, hotplug_callback, nullptr, &hotplug_handle);
+
+ if (rc != LIBUSB_SUCCESS) {
+ LOG(FATAL) << "failed to register libusb hotplug callback";
+ }
+
+ adb_notify_device_scan_complete();
+
// Spawn a thread for libusb_handle_events.
std::thread([]() {
adb_thread_setname("libusb");
@@ -412,24 +424,10 @@
libusb_handle_events(nullptr);
}
}).detach();
-
- // Spawn a thread to do device enumeration.
- // TODO: Use libusb_hotplug_* instead?
- std::unique_lock<std::mutex> lock(device_poll_mutex);
- device_poll_thread = new std::thread(poll_for_devices);
}
void usb_cleanup() {
- {
- std::unique_lock<std::mutex> lock(device_poll_mutex);
- terminate_device_poll_thread = true;
-
- if (!device_poll_thread) {
- return;
- }
- }
- device_poll_cv.notify_all();
- device_poll_thread->join();
+ libusb_hotplug_deregister_callback(nullptr, hotplug_handle);
}
// Dispatch a libusb transfer, unlock |device_lock|, and then wait for the result.