Samsung Semiconductor (SSIR) Interview Experience for BSP Driver (5+ Years Experience)

Round 1:

• Whole suspend process: Interaction between user space and kernel space, what values are modified, how to handle wrong values, which API is called, suspend states, bottom current issues
• CPU Idle c states
• CPU DVFS working, how DVFS decides about Freq and voltage, how the system increases the Freq
• Idle states supported, when which state will go, who puts in idle state, how power is saved in such scenario
• I/O question of pointer
• Extract k bits from a given number in a given range

Puzzle: 

• Torch and bridge
• Guess Color of Hat
• Candle burning

Round 2:

• Suspend process explain: questions related to it
• CPU hotplug
• Arm V8 architecture
• Interrupts and types of interrupts
• Microcontroller and SoC
• SMC call vs PSCI call
• 2 i/o questions of call by value and call by reference
• Tasklet, Workqueue
• Types of locks used
• Kernel panic vs oops
• How i2c driver will handle suspend the process
• User space and kernel space interaction
• How to port on latest kernel knowing that some codes is already present in mainline
• LDO vs BUCK
• Softirq, Bottom Halve
• Topological sorting
• Write Fibonacci using recursion and DP
• Reverse LL using recursion and normal
• DFS BFS
• Null vs void vs Wild pointer
• Hypervisor
• Arguments provided in SMC calls, how this is interpreted in secure world