According to ASUI settings, there is no 'restart' for dsp-init. Try 'start' or 'stop' and then 'start' or try using ASUI settings service manager, the service is called "AUDIO -- DSP".

Edit: In case anyone cares http://maemo.qzx.com/service-matrix.png - the BSR columns are boot, start/stop, restart. The numeric columns are start runlevels and stop runlevels.