IGN:Allow drivers to perform arbitrary post id match checks to detect devices

src/calibre/devices/interface.py

@@ -41,6 +41,20 @@ class Device(object):
         '''Return the FDI description of this device for HAL on linux.'''
         return ''
     
+    @classmethod
+    def can_handle(cls, device_info):
+        '''
+        Optional method to perform further checks on a device to see if this driver
+        is capable of handling it. If it is not it should return False. This method
+        is only called after the vendor, product ids and the bcd have matched, so
+        it can do some relatively time intensive checks. The default implementation
+        returns True.
+        
+        :param device_info: On windows a device ID string. On Unix a tuple of 
+        ``(vendor_id, product_id, bcd)``. 
+        '''
+        return True
+    
     def open(self):
         '''
         Perform any device specific initialization. Called after the device is

src/calibre/devices/scanner.py

@@ -63,12 +63,14 @@ class DeviceScanner(object):
             for device_id in self.devices:
                 if vid in device_id and pid in device_id:
                     if self.test_bcd_windows(device_id, getattr(device, 'BCD', None)):
-                        return True
+                        if device.can_handle(device_id):
+                            return True
         else:
             for vendor, product, bcdDevice in self.devices:
                 if device.VENDOR_ID == vendor and device.PRODUCT_ID == product:
                     if self.test_bcd(bcdDevice, getattr(device, 'BCD', None)):
-                        return True
+                        if device.can_handle((vendor, product, bcdDevice)):
+                            return True
         return False