Speed up device detection in windows and Fix #2287 (Calibre 0.5.7 No Longer Detects Kindle 2 When Plugged In)

src/calibre/devices/prs505/driver.py

@@ -150,7 +150,7 @@ def open_windows(self):
         time.sleep(6)
         drives = []
         wmi = __import__('wmi', globals(), locals(), [], -1)
-        c = wmi.WMI()
+        c = wmi.WMI(find_classes=False)
         for drive in c.Win32_DiskDrive():
             if self.__class__.is_device(str(drive.PNPDeviceID)):
                 if drive.Partitions == 0:

src/calibre/devices/usbms/device.py

@@ -186,7 +186,7 @@ def open_windows(self):
         time.sleep(6)
         drives = {}
         wmi = __import__('wmi', globals(), locals(), [], -1)
-        c = wmi.WMI()
+        c = wmi.WMI(find_classes=False)
         for drive in c.Win32_DiskDrive():
             if self.windows_match_device(str(drive.PNPDeviceID), self.WINDOWS_MAIN_MEM):
                 drives['main'] = self.windows_get_drive_prefix(drive)

src/calibre/gui2/device.py

@@ -11,6 +11,7 @@
                      Qt
 
 from calibre.devices import devices
+from calibre.constants import iswindows
 from calibre.gui2.dialogs.choose_format import ChooseFormatDialog
 from calibre.parallel import Job
 from calibre.devices.scanner import DeviceScanner
@@ -69,7 +70,14 @@ def detect_device(self):
             if connected and not device[1]:
                 try:
                     dev = device[0]()
-                    dev.open()
+                    if iswindows:
+                        import pythoncom
+                        pythoncom.CoInitialize()
+                    try:
+                        dev.open()
+                    finally:
+                        if iswindows:
+                            pythoncom.CoUninitialize()
                     self.device       = dev
                     self.device_class = dev.__class__
                     self.connected_slot(True)