Method and non-transitory computer-readable storage medium and apparatus for handling garbage collection process

A method for handling a garbage collection (GC) process, performed by a processing unit of a flash controller, wherein a portable storage device is equipped with the flash controller and a flash module, the method comprising:

• detecting that the portable storage device is inserted into a host equipment;
• operating the portable storage device in a working state;
• obtaining a maximum transmission bandwidth of a host interface (I/F), wherein the flash controller comprises the host I/F, and the host I/F is coupled to the host equipment;
• determining whether a transmission bandwidth of a flash I/F is higher than the maximum transmission bandwidth of the host I/F, wherein the flash controller comprises the flash I/F, and the flash I/F is coupled to the flash module;
• in response to a determination that the transmission bandwidth of the flash I/F is higher than the maximum transmission bandwidth of the host I/F, inserting a plurality of operations of the GC process during an execution of a host command in the working state;
• resetting a working expiration timer for counting a specified period of time each time after receiving any host command from the host equipment through the host I/F;
• and
• in response to detecting that the working expiration timer reaches the specified period of time, causing the portable storage device to leave the working state and enter a power saving state, wherein the plurality of operations of the GC process are not performed in the power saving state.