graey
Posts: 5
Joined: Mon Mar 19, 2018 3:17 pm

Re: Sleep Mode - and or turn off backlight?

Mon Mar 19, 2018 8:13 pm

I am currently running Raspbian Stretch and I'm using the official 7" touch display.

By default, raspbian would turn off the display (including backlights) after some timeout (30 min I believe). At some point, I installed xscreensaver to see what my options were, but eventually decided I preferred to have the screen actually turn off rather than use a screen saver. The problem is, the best I can get now that I have installed xscreensaver is to have a black screen with the backlight LEDs still on. I have tried using xcreensaver "Blank Screen Only", I have also tried "Blank Screen Only" in conjunction with Power Management and "Quick Power-Off in Blank Only Mode." But I still get black screen with backlight LEDs at full brightness.

How do I restore the original functionality of turning off the display, including backlight LEDs?

edit: I should add that I have also tried uninstalling xscreensaver, which did not revert the system back to default settings.

edit 2: I updated my firmware to 4.14.27 from 4.9.59 with no change in automatic behavior. I also have verified the existence of /sys/class/backlight/rpi_backlight/bl_power, brightness, etc. I can also successfully update the values within these files, but they seem to have NO EFFECT at all on my screen brightness or backlight. I am also using a screen with a V1.1 controller board.

TIA!
I'm better than dirt... well most dirt. Not that fancy store bought stuff, I can't compete with that... full of nutrients and everything. -Moe Sizlack

Zoandar
Posts: 58
Joined: Sat Apr 06, 2013 9:41 pm

Re: Sleep Mode - and or turn off backlight?

Tue Mar 20, 2018 4:02 am

May I ask if you good folks running Debian Stretch have access to the display brightness control? Reading this thread leaves me uncertain of that. I am looking to adjust my display. I am running Debian Stretch on a Pi 3 inside a "Pi-Top" notebook which has its own attached display and keyboard. When I installed the Debian Stretch with desktop image directly to the SD, there were no system controls for things like display brightness. I am now trying a re-install thru NOOBS (some of you mentioned some success in your back-light endeavors after using NOOBS). Just wondering if this might finally give me what I seek.

If not, I'll keep looking for other distros until I find one that offers these controls. I seek an alternative to the Pi-Top Polaris OS, since much of their software seems buggy when I try to use it. Their support system is, well, "abysmal" would be a good word to describe it over the past year, from my point of view.
- Zoandar -
Current:
Pi-Top Notebook with Pi 3 B v. 1.2
Older hardware:
Rpi Rev B - 512 MB with Rev 2 GertBoard

junes
Posts: 1
Joined: Sat May 12, 2018 3:04 pm

Re: Sleep Mode - and or turn off backlight?

Sat May 12, 2018 3:06 pm

graey wrote:
Mon Mar 19, 2018 8:13 pm
I am currently running Raspbian Stretch and I'm using the official 7" touch display.

By default, raspbian would turn off the display (including backlights) after some timeout (30 min I believe). At some point, I installed xscreensaver to see what my options were, but eventually decided I preferred to have the screen actually turn off rather than use a screen saver. The problem is, the best I can get now that I have installed xscreensaver is to have a black screen with the backlight LEDs still on. I have tried using xcreensaver "Blank Screen Only", I have also tried "Blank Screen Only" in conjunction with Power Management and "Quick Power-Off in Blank Only Mode." But I still get black screen with backlight LEDs at full brightness.

How do I restore the original functionality of turning off the display, including backlight LEDs?

edit: I should add that I have also tried uninstalling xscreensaver, which did not revert the system back to default settings.

edit 2: I updated my firmware to 4.14.27 from 4.9.59 with no change in automatic behavior. I also have verified the existence of /sys/class/backlight/rpi_backlight/bl_power, brightness, etc. I can also successfully update the values within these files, but they seem to have NO EFFECT at all on my screen brightness or backlight. I am also using a screen with a V1.1 controller board.

TIA!
I would be interested in the same as well. Installed the xscreensaver after initial setup, but would like to make it possible for display to turn off backlight and blank when it is not used, and wake up on next touch.

bioapi
Posts: 1
Joined: Tue Jan 21, 2020 3:48 pm

Re: Sleep Mode - and or turn off backlight?

Tue Jan 21, 2020 3:54 pm

junes wrote:
Sat May 12, 2018 3:06 pm
I would be interested in the same as well. Installed the xscreensaver after initial setup, but would like to make it possible for display to turn off backlight and blank when it is not used, and wake up on next touch.
quite easy:

Code: Select all

xset s 10 && xset -dpms
for 10 seconds touchscreen timeout and will wakeup on touch

sicvolo
Posts: 4
Joined: Wed May 01, 2013 11:20 pm

Re: Sleep Mode - and or turn off backlight?

Mon Aug 24, 2020 5:26 pm

One way to solve this issue is with the tool that syncs touchscreen backlight with the screensaver - https://github.com/alexivkin/rpi-backlight-sync

jharris1993
Posts: 255
Joined: Sat Oct 05, 2013 10:26 pm

Re: Sleep Mode - and or turn off backlight?

Wed Oct 14, 2020 9:25 pm

I found this topic via a link on a different site that described how to adjust its brightness. And just in case anyone's interested, I'm typing this up on a Pi-4 running the 7" display - not sure what version, but it's at least a 1.1. I also have the "official" enclosure for the 7" display.

I like the 7" display/enclosure because I can fuss with the Pi without having to dig up a monitor or fuss with HDMI cables and adapters since many of my displays don't support HDMI. Add a Pi keyboard/mouse and it's almost as good as a laptop.

A question.
I noticed that the /sys/class/backlight/rpi_backlight directory contains several files and a "power" directory.

Code: Select all

root@raspberrypi:/sys/class/backlight/rpi_backlight# ls -la
total 0
drwxr-xr-x 3 root root    0 Oct 14 23:27 .
drwxr-xr-x 3 root root    0 Oct 14 23:27 ..
-r--r--r-- 1 root root 4096 Oct 14 23:28 actual_brightness
-rw-r--r-- 1 root root 4096 Oct 14 23:28 bl_power
-rw-r--r-- 1 root root 4096 Oct 14 22:39 brightness
lrwxrwxrwx 1 root root    0 Oct 14 23:28 device -> ../../../rpi_backlight
-r--r--r-- 1 root root 4096 Oct 14 23:28 max_brightness
drwxr-xr-x 2 root root    0 Oct 14 23:28 power
-r--r--r-- 1 root root 4096 Oct 14 23:28 scale
lrwxrwxrwx 1 root root    0 Oct 14 23:28 subsystem -> ../../../../../class/backlight
-r--r--r-- 1 root root 4096 Oct 14 23:28 type
-rw-r--r-- 1 root root 4096 Oct 14 23:28 uevent
root@raspberrypi:/sys/class/backlight/rpi_backlight# 
And the "power" directory contains:

Code: Select all

root@raspberrypi:/sys/class/backlight/rpi_backlight/power# ls -la
total 0
drwxr-xr-x 2 root root    0 Oct 14 23:28 .
drwxr-xr-x 3 root root    0 Oct 14 23:27 ..
-rw-r--r-- 1 root root 4096 Oct 14 23:29 autosuspend_delay_ms
-rw-r--r-- 1 root root 4096 Oct 14 23:29 control
-r--r--r-- 1 root root 4096 Oct 14 23:29 runtime_active_time
-r--r--r-- 1 root root 4096 Oct 14 23:29 runtime_status
-r--r--r-- 1 root root 4096 Oct 14 23:29 runtime_suspended_time
root@raspberrypi:/sys/class/backlight/rpi_backlight/power# 
. . . all of these things are potentially interesting, like "control" which returns "auto" when read via "cat".

Is any of this documented anywhere? It would be nice to know what values, if any, can be written to these "files" and what control, if any, they have over the display.

Thanks!
Jim "JR"

Some see things as they are, and ask "Why?"
I dream things that never were, and ask "Why Not".

Robert F. Kennedy

“Impossible” is only found in the dictionary of a fool.
Old Chinese Proverb

jharris1993
Posts: 255
Joined: Sat Oct 05, 2013 10:26 pm

Re: Sleep Mode - and or turn off backlight?

Fri Oct 16, 2020 10:43 am

BTW

For everyone complaining about the 7" display, there are other touchscreens for the Pi.

Adafruit has several as noted above.
SparkFun may have some, and there are others as well - like the Vellmann 3.5" touchscreen display "hat" that I bought.

[Picture of my Vellmann VMP400 3.5" touchscreen that's too big to upload :(]
Jim "JR"

Some see things as they are, and ask "Why?"
I dream things that never were, and ask "Why Not".

Robert F. Kennedy

“Impossible” is only found in the dictionary of a fool.
Old Chinese Proverb

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