Is it possible to turn off display.

[vman56]

The Raspberry has a vcgencmd which, among other things, purports to let to disable the display to save power.  I run my SBCs headless most of the time, does TinkerOS have an equivalent method of shutting down the display?

Along those lines, what's the best way to detect when a USB keyboard is present?

[mcerveny]

Power management is slightly complicated but fully automatic (at least in rockchip-4.4). Check video power management status:

Code:

# cat /sys/kernel/debug/pm_genpd/pm_genpd_summary
domain                          status          slaves
   /device                                             runtime status
----------------------------------------------------------------------
pd_gpu                          off            
   /devices/platform/ffa30000.gpu                      suspended
pd_video                        on              
   /devices/platform/ff9a0800.iommu                    unsupported
   /devices/platform/ff9a0000.vpu-service              suspended
pd_hevc                         on              
   /devices/platform/ff9c0440.iommu                    unsupported
   /devices/platform/ff9c0000.hevc-service             suspended
pd_vio                          on              
   /devices/platform/ff930300.iommu                    unsupported
   /devices/platform/ff940300.iommu                    unsupported
   /devices/platform/ff920000.rga                      suspended
   /devices/platform/ff980000.hdmi                     active
   /devices/platform/ff930000.vop                      active
   /devices/platform/ff940000.vop                      suspended

- if you unplug hdmi connector "vop" is suspended ("vop" - visual output processor)
- if your console goes to powersave/off "vop" is suspended
- if you run "3d" application (for example chrome browser webgl) "gpu" is activated
- if you encode/decode "h264 ..."  "vpu-service" is activated
- if you decode "hevc"  "hevc-service" is activated

What exactly do you need to power suspend ?

USB keyboard ? What do you need to check ?

Code:

# lsusb
# ls /dev/input/by-id/
# ls /dev/input/by-path/
# ls /dev/input/by-path/*usb*kbd
/dev/input/by-path/platform-ff540000.usb-usb-0:1.1:1.0-event-kbd