root@debian:~# cat /sys/kernel/debug/dri/0/i915_power_domain_info
Power well/domain         Use count
always-on                 -2
  PIPE_A                  1
  TRANSCODER_EDP          1
  PORT_DDI_A_2_LANES      0
  PORT_DDI_A_4_LANES      -4
  PORT_DDI_B_2_LANES      0
  PORT_DDI_B_4_LANES      0
  PORT_DDI_C_2_LANES      0
  PORT_DDI_C_4_LANES      0
  PORT_DDI_D_2_LANES      0
  PORT_DDI_D_4_LANES      0
  PORT_CRT                0
  INIT                    0
display                   0
  PIPE_B                  0
  PIPE_C                  0
  PIPE_A_PANEL_FITTER     0
  PIPE_B_PANEL_FITTER     0
  PIPE_C_PANEL_FITTER     0
  TRANSCODER_A            0
  TRANSCODER_B            0
  TRANSCODER_C            0
  PORT_DSI                0
  PORT_OTHER              0
  VGA                     0
  AUDIO                   0
  INIT                    0