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Commit 998fc295 authored by Jeremy Wu's avatar Jeremy Wu
Browse files

UsbAlsaManager: wait for device address on usb added 

Currently, when a USB audio device is attached, the framework scans all
available cards in `/proc/asound/cards` and uses this information to
further query and determine if the corresponding device is registered in
`/dev/snd/`.

However, there is some delay in the update of available cards, so in
this CL we wait until the scan results actually include some card that
has the corresponding address.

Bug: 378826805
Flag: com.android.server.usb.flags.wait_for_alsa_scan_results_if_has_audio_interface
Test: plug usb audio device multiple times
Change-Id: I718e5f7874856f0e0037459b29ebe1238e129c46
parent 40af2bbb

services/usb/java/com/android/server/usb/UsbAlsaManager.java

+79 −12
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ import android.util.Slog; 
import com.android.internal.alsa.AlsaCardsParser;

import com.android.internal.util.dump.DualDumpOutputStream;

import com.android.server.usb.descriptors.UsbDescriptorParser;

import com.android.server.usb.flags.Flags;



import libcore.io.IoUtils;
@@ -294,15 +295,32 @@ public final class UsbAlsaManager { 
            UsbDescriptorParser parser) {

        if (DEBUG) {

            Slog.d(TAG, "usbDeviceAdded(): " + usbDevice.getManufacturerName()

                    + " nm:" + usbDevice.getProductName());

                    + " nm:" + usbDevice.getProductName()

                    + " hasAudioInterface: " + parser.hasAudioInterface());

        }



        AlsaCardsParser.AlsaCardRecord cardRec = null;



        if (Flags.waitForAlsaScanResultsIfHasAudioInterface()) {

            if (!parser.hasAudioInterface()) {

                return;

            }



            waitForAlsaDeviceAddress(deviceAddress, true /*isAdded*/);



            // Find the ALSA spec for this device address

            cardRec = mCardsParser.findCardNumFor(deviceAddress);



            if (cardRec == null) {

                Slog.e(TAG, "usbDeviceAdded(): cannot find sound card for " + deviceAddress);

                return;

            }

        } else {

            // Scan the Alsa File Space

            mCardsParser.scan();



            // Find the ALSA spec for this device address

        AlsaCardsParser.AlsaCardRecord cardRec =

                mCardsParser.findCardNumFor(deviceAddress);

            cardRec = mCardsParser.findCardNumFor(deviceAddress);

            if (cardRec == null) {

                if (parser.hasAudioInterface()) {

                    Slog.e(TAG, "usbDeviceAdded(): cannot find sound card for " + deviceAddress);
@@ -311,6 +329,7 @@ public final class UsbAlsaManager { 
            }



            waitForAlsaDevice(cardRec.getCardNum(), true /*isAdded*/);

        }



        // Add it to the devices list

        boolean hasInput = parser.hasInput()
@@ -417,7 +436,11 @@ public final class UsbAlsaManager { 
        UsbAlsaDevice alsaDevice = removeAlsaDevice(deviceAddress);

        Slog.i(TAG, "USB Audio Device Removed: " + alsaDevice);

        if (alsaDevice != null) {

            if (Flags.waitForAlsaScanResultsIfHasAudioInterface()) {

                waitForAlsaDeviceAddress(deviceAddress, false /*isAdded*/);

            } else {

                waitForAlsaDevice(alsaDevice.getCardNum(), false /*isAdded*/);

            }

            deselectAlsaDevice(alsaDevice);

            if (IS_MULTI_MODE) {

                selectDefaultDevice(alsaDevice.getOutputDeviceType());
@@ -464,6 +487,50 @@ public final class UsbAlsaManager { 
        }

   }



    private boolean waitForAlsaDeviceAddress(String addr, boolean isAdded) {

        if (DEBUG) {

            Slog.e(TAG, "waitForAlsaDeviceAddress(" + addr + ")");

        }



        // This value was empirically determined.

        final int kWaitTimeMs = 2500;



        synchronized (mAlsaCards) {

            final long timeoutMs = SystemClock.elapsedRealtime() + kWaitTimeMs;



            do {

                mCardsParser.scan();



                AlsaCardsParser.AlsaCardRecord cardRec =

                        mCardsParser.findCardNumFor(addr);



                if (isAdded && (cardRec != null)) {

                    if (mAlsaCards.contains(cardRec.getCardNum())) {

                        return true;

                    }

                }



                // Consider removed if can't be probed by the parser as

                // it's not as time sensitive for the removal case.

                if (!isAdded && (cardRec == null)) {

                    return true;

                }



                long waitTimeMs = timeoutMs - SystemClock.elapsedRealtime();

                if (waitTimeMs <= 0) {

                    Slog.e(TAG, "waitForAlsaDeviceAddress(" + addr + ") timeout");

                    return false;

                }



                try {

                    mAlsaCards.wait(waitTimeMs);

                } catch (InterruptedException e) {

                    Slog.d(TAG, "usb: InterruptedException while waiting for ALSA file.");

                }

            } while (true);

        }

    }



    private boolean waitForAlsaDevice(int card, boolean isAdded) {

        if (DEBUG) {

            Slog.e(TAG, "waitForAlsaDevice(c:" + card + ")");