A system comprises a plurality of processor cores. The processor cores may comprise one or more application processor (AP) cores and a boot strap processor (BSP) core. A basic input/output system (BIOS) comprises an I/O device module to call a stall function in response to an I/O operation, a power management module that couples to the I/O device and a timer module that couples to the power management module. The power management module is to adjust a timer period of the timer module based on a stall delay of the stall function. The power management module may hook the stall function and compare the stall delay with a predetermined threshold and set the timer period to the stall delay in response to determining that the stall delay is longer. The power management module may put the BSP in a sleep mode during the timer period to save power.