Merge "Don't call setInterface when querying protocol"

1 files changed, 5 insertions, 6 deletions

diff --git a/services/usb/java/com/android/server/usb/UsbUniversalMidiDevice.java b/services/usb/java/com/android/server/usb/UsbUniversalMidiDevice.java
index db0c80f189d3..13d404caf6a2 100644
--- a/services/usb/java/com/android/server/usb/UsbUniversalMidiDevice.java
+++ b/services/usb/java/com/android/server/usb/UsbUniversalMidiDevice.java
@@ -218,14 +218,13 @@ public final class UsbUniversalMidiDevice implements Closeable {
             if (doesInterfaceContainInput
                     && doesInterfaceContainOutput) {
                 UsbDeviceConnection connection = manager.openDevice(mUsbDevice);
-                if (!connection.claimInterface(interfaceDescriptor.toAndroid(mParser), true)) {
-                    Log.d(TAG, "Can't claim control interface");
-                    continue;
-                }
+
+                // The ALSA does not handle switching to the MIDI 2.0 interface correctly
+                // and stops exposing /dev/snd/midiC1D0 after calling connection.setInterface().
+                // Thus, simply use the control interface (interface zero).
                 int defaultMidiProtocol = mMidiBlockParser.calculateMidiType(connection,
-                        interfaceDescriptor.getInterfaceNumber(),
+                        0,
                         interfaceDescriptor.getAlternateSetting());
-
                 connection.close();
                 return defaultMidiProtocol;
             }