All Subtasks Estimation for a Story in Sprint Planning is it essential? or only planning sub tasks which are in scope of sprint

Hi Everyone,

I have stories in my backlog prioritized for sprint planning

For clear understanding of what work gets done by whom, we have broken work of story down to sub tasks(one sub task per person)

Now within a story of a sprint, Lets say I clearly know out of 2 sub-tasks, completing only 1 is possible

Example: Story with 2 subtasks one for dev+one for qa and  only dev is possible to be completed within sprint

Should i plan and estimate both sub tasks of the story or only the ones I clearly know is possible in scope of sprint?