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Commit c4714fc6 authored by Phil Burk's avatar Phil Burk Committed by Eric Laurent
Browse files

qcom/audio/hal: add offset to MMAP time 

Try to fix glitches on AAudio MMAP input on some devices.
The DSP is returning a position/time pair that is too soon.

Bug: 122680738
Test: Should see glitch.count = 0 when you run this test.
Test: adb shell aaudio_loopback -tm -s20

Change-Id: Ib4c5b773702923ef76da124a5c6f4773e004ed7e
parent 409f07c0

hal/audio_hw.c

+19 −0
Original line number Diff line number Diff line
@@ -4427,6 +4427,21 @@ static int in_start(const struct audio_stream_in* stream) 
    return ret;

}



// Read offset for the input positional timestamp from a property.

// This is to workaround apparent inaccuracies in the timing info that

// are causing glitches.

static int64_t in_get_mmap_time_offset() {

    // Roughly 100 usec is needed on some devices to cover inaccuracy in DSP.

    // This should be set in a property. But I cannot read the property!

    // So I am setting the offset here to 101 as a test.

    const int32_t kDefaultOffsetMicros = 101; // should be zero if no bug

    // FIXME - why is the property not being read?! The default is used.

    int32_t mmap_time_offset_micros = property_get_int32(

        "persist.audio.in_mmap_delay_micros", kDefaultOffsetMicros);

    ALOGI("in_get_mmap_time_offset set to %d micros", mmap_time_offset_micros);

    return mmap_time_offset_micros * (int64_t)1000;

}



static int in_create_mmap_buffer(const struct audio_stream_in *stream,

                                  int32_t min_size_frames,

                                  struct audio_mmap_buffer_info *info)
@@ -4507,6 +4522,8 @@ static int in_create_mmap_buffer(const struct audio_stream_in *stream, 
        goto exit;

    }



    in->mmap_time_offset_nanos = in_get_mmap_time_offset();



    in->standby = false;

    ret = 0;
@@ -4550,6 +4567,8 @@ static int in_get_mmap_position(const struct audio_stream_in *stream, 
        goto exit;

    }

    position->time_nanoseconds = audio_utils_ns_from_timespec(&ts);

    position->time_nanoseconds += in->mmap_time_offset_nanos;



exit:

    pthread_mutex_unlock(&in->lock);

    return ret;

hal/audio_hw.h

+1 −0
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ struct stream_in { 
    bool enable_ns;

    int64_t frames_read; /* total frames read, not cleared when entering standby */

    int64_t frames_muted; /* total frames muted, not cleared when entering standby */

    int64_t mmap_time_offset_nanos; /* fudge factor to correct inaccuracies in DSP */



    audio_io_handle_t capture_handle;

    audio_input_flags_t flags;