Made fan starts smoother when reaches 50 degrees in auto mode

In the old code when CPU reaches 50 degrees fan->duty changes from 1 to (255 * 50 / 80 = 159), that's cooling fast CPU by 1 degree again to 50 and cooler stops, and so on... This noise is annoying and may be this algorithm would be better?

When temperature is above 50 - everything is doing like it did before. After 50 degrees duty would be in interval [1, 255] instead of [159, 255]. But there would be a problem, that CPU will be cooling much less in temperature about 50-60. Well, it can be fixed by setting FAN_TEMP_START to 40 or 35 degrees.