Linux QAudioOutput playback stuttering

Playing an audio clip using QAudioOutput on Linux (i.e. through ALSA) stutters on some hardware/software configurations. Playing the same audio clip on the same system using "aplay" works correctly.

The problem appears to be that the buffer size and period size are being set to equal values – the buffer size should be larger than the period size:

# cat /proc/asound/card0/pcm0p/sub0/hw_params
access: MMAP_INTERLEAVED
format: S16_BE
subformat: STD
channels: 2
rate: 11025 (11025/1)
period_size: 4096
buffer_size: 4096
tick_time: 4000

I've attached a patch to the ALSA implementation of QAudioOutput which produces correct results for me.

I've also attached source code for a test application that demonstrates the bug on my PowerPC machine. This same code works correctly without any change to Qt on my i386 desktop.