@linusg Hi, yes, that helps very much. I've been working on this for 2 hours so far and seem to hit a roadblock. I will keep this pull request open this time and we can work in this one, as I closed the last one

First, I'd like to check in with you and make sure I am following your plan so far.

Second, I can't seem to get this to work

if((self._board_type == BoardType.TINKER_BOARD)

Can you see if I am doing something bad with enum? I cant seem to get it to work unless I do

if((self._board_type.name == "TINKER_BOARD")

BTW, I couldnt use auto for enum, I think it is not supported on my Tinkerboard... Was not able to import it.

I have added a new function, Toggle() I have also added support for Asus Tinkerboard and Asus Tinkerboard S Maybe you want to add a switch statement so support can be offered for both OS in 1 file. This pull request is in case you like any of my changes.

Thank you so much for this great piece of work!

It runs great on a small touch screen that I built as a clock for my mother who is getting old and keeps forgetting what day it is... I run AppDaemon with Home Assistant on the device. Unfortunately, Home Assistant and AppDaemon are running in dock images and cannot control the host system and hence have no control over the display. Home Assistant would have beentje perfect companion to dim the screen in the evenings... Is there a way to send the commands to the screen remotely? It is not possible to connect with ssh from docker image to host system. MQTT would be fine, for example...

rpi-backlight worked in debian buster, but not on bullseye. Installing gives this notification:

Defaulting to user installation because normal site-packages is not writeable Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple Collecting rpi-backlight Downloading https://www.piwheels.org/simple/rpi-backlight/rpi_backlight-2.4.1-py3-none-any.whl (9.8 kB) Installing collected packages: rpi-backlight Successfully installed rpi-backlight-2.4.1

After installation i gave the command:"echo 'SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power"' | sudo tee -a /etc/udev/rules.d/backlight-permissions.rules" and a reboot, when i give the command backlight -b5 it is saying it doesn't excist. With rpi-backlight -b5 it is saying:"

Traceback (most recent call last): File "/home/pi/.local/bin/rpi-backlight", line 8, in sys.exit(main()) File "/home/pi/.local/lib/python3.9/site-packages/rpi_backlight/cli.py", line 78, in main backlight = Backlight( File "/home/pi/.local/lib/python3.9/site-packages/rpi_backlight/init.py", line 75, in init self._max_brightness = self._get_value("max_brightness") # 255 File "/home/pi/.local/lib/python3.9/site-packages/rpi_backlight/init.py", line 92, in _get_value raise e File "/home/pi/.local/lib/python3.9/site-packages/rpi_backlight/init.py", line 84, in _get_value return int((self._backlight_sysfs_path / name).read_text()) File "/usr/lib/python3.9/pathlib.py", line 1255, in read_text with self.open(mode='r', encoding=encoding, errors=errors) as f: File "/usr/lib/python3.9/pathlib.py", line 1241, in open return io.open(self, mode, buffering, encoding, errors, newline, File "/usr/lib/python3.9/pathlib.py", line 1109, in _opener return self._accessor.open(self, flags, mode) FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/backlight/rpi_backlight/max_brightness'

In /sys/class there is a directory "backlight", but no directory "rpi_backlight". Only a directory "10-0045" Has this to do with a new video-driver in the debian bullseye?

Thanks in advance.

Hi Linus, I have taken a stab at implementation. It works!

A few points for you to review -I am not sure if I did the enumeration to your liking. -I removed the part in the readme, now that it works out of the box. -After I blacked the files, it rearranged the whitespace on your argument parser -I didnt know if I should put the _get_board in the Backlight class. I'm not very good with OOP, so I was not able to access it with self._get_board(). My guess is because it hasn't been init'd yet.

Thanks,

Fixes #30

Hi Linus, been a while. Hope all is well. I have recently purchased a Tinkerboard 2 and am adding support for it. I'd like you to check over the changes and make sure its implemented how youd like. If not, I am happy to make any changes.

Hey everyone,

I managed to run the code to change screen brightness and every thing works fine.

However for low brightness values (<100) the screen power supply starts emitting some noise. Any one knows why ? Could it be related to brightness being the screen turning on et off quickly so the power supply becomes some kind of square signal ?

The path to the backlight is now /sys/class/backlight/10-0045/brightness due to the swap to KMS in Bullseye, which resulted in a file not found error when executing a command.

This is a quick and dirty fix to dynamically fix the control path.

Further fleshing out our discussion of automatic board detection/initiation so hopefully we don't need to manually initiate the board, in both init and CLI files.

I suppose if there's a reliable way to detect the board type, we could have automatic detection if no board type is explicitly provided - perhaps by checking the existence of each path in _BACKLIGHT_SYSFS_PATHS?

I was thinking of using /proc/device-tree/model

root@Harbormaster:~# cat /proc/device-tree/model
ASUS Tinker Board 2 (Linux Opensource)

What is the output on the Pi?

Hi Linus! I have ran the following command:

echo 'SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power /sys/devices/platform/ff150000.i2c/i2c-3/3-0045/tinker_mcu_bl
"' | sudo tee -a /etc/udev/rules.d/backlight-permissions.rules

Note, I ran for both the TinkerBoard and the Pi files, as all files exist on my OS. This does not fix the permissions for me.

Sidenote, I actually had to replace the %k with rpi_backlight:

echo 'SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/rpi_backlight/brightness /sys/class/backlight/rpi_backlight/bl_power /sys/devices/platform/ff150000.i2c/i2c-3/3-0045/tinker_mcu_bl
> "' | sudo tee -a /etc/udev/rules.d/backlight-permissions.rules

as I got:

chmod: cannot access '/sys/class/backlight/%k/brightness': No such file or directory
chmod: cannot access '/sys/class/backlight/%k/bl_power': No such file or directory

Just wondering if you have any idea why both the udev rule wouldn't work, nor the %k in that rule?

• Function _denormalize_brightness does not clamp the output to the normal 0-255 int() range. Force-clamped 0-255 now.
• Function _normalize_brightness does not clamp the output to the normal 0-100 percent range. Force-clamped 0-100 now.
• In @brightness.setter, the while loop looks only for current_value != value. In some circumstances, it won't stop incrementing. Hard-clamped to 0-100 percent range.

Hi Linus, On my Pi4, I am able to successfully fade with a duration with rpi-backlight -b 0 -d 3. However, I cant power on/off with a duration rpi-backlight -p off -d 3. I can, however, toggle with a duration just fine rpi-backlight -p toggle -d 3 I believe we should be able to power on/off with a duration based on this line in the code, showing the intention that power setting may indeed be set with a duration. parser.error("-p/--set-power may only be used with -d/--duration")

After checking the code, I found that powering on/off with a duration wasn't actually implemented yet So, I added it as a feature: -Power on/off is now supported with duration

Additionally, I found that if you set the brightness to 100 while the power is off, nothing happens. So, I added an extra 2 features: -If setting brightness >0, turn the power on first. (This will better the user experience) -If setting brightness to 0, turn the power off once brightness is 0. (Perhaps $ energy savings?)

I also added a quick check to the code. -Do not try to power on if already on (This will prevent the brightness from setting to 100 if brightness is already turned up (i.e. 40) and you try to power on) which fixes #44

If the screen is on and the command power off is sent, the screen is back to the former brightness when turned on again.

For example:

// Brightness 20%
rpi-backlight --p off //screen blank
rpi-backlight --p on // screen 20%

Toggle does not remember the former brightness:

// Brightness 20%
rpi-backlight --p toggle //screen blank
rpi-backlight --p toggle // screen 100%

Is this intentional? I would prefer the previous setting to be remembered.