After digging through the assembler files it seems that its __old_snd_pcm_hw_params_get_period_size that is called. sub r3, fp, #28 sub r2, fp, #32 ldr r0, [fp, #-40] mov r1, r3 bl snd_pcm_hw_params_get_period_size mov r3, r0 str r3, [fp, #-20]