1.Disable the transmitter.
TRANSMITTER_ENABLE = 0x00
2.Set DisplayPort clock speed.
PHY_CLOCK_SELECT = desired link speed
3.Wait for the PHY rate change done and PLL lock.
a.PHY_STATUS bits [3:0] = 4'b1111 (for two lanes) or PHY_STATUS bits [3:0] = 4'b0101 (for one lane)
b.PHY_STATUS bits  = 1'b1
4.Enable the transmitter.
TRANSMITTER_ENABLE = 0x01
Note: If the current PS-GTR rate is 1.62 Gb/s and you try to set it again to 1.62 Gb/s, the DP.DP_PHY_STATUS [RATE_CHANGE_DONE_0_1] bits will not be set. The PS-GTR reset doesn’t need to be explicitly issued from the software during a dynamic link rate change, it is handled inside the PS-GTR. Therefore, unless the phy configuration changes the link rate from existing value to the desired value, the RATE_CHANGE_DONE_0_1bits won’t be set.