Prepare the slow cooker liner with non stick cooking spray. In a medium bowl, mix together the brown gravy mix, onion soup mix, and cream of mushroom soup. Spoon half of this on the bottom.
Place half of the pork loin chops on top of that. Top with the sliced mushrooms. Put the final layer of pork loin chops on top of that. Pour the remaining soup mixture over the top.
Cover the slow cooker and cook on low for 5 to 6 hours (timing depends on how thick yours are). Serve the pork loin chops with the gravy over mashed potatoes, stuffing, or rice.