After a few moments the time is outdated

Troubleshooting
1

Creating a bug report/issue

Required Information

  • DietPi version | v8.17.2
  • Distro version | bullseye
  • Kernel version | 6.1.21-v8+ #1642 SMP PREEMPT Mon Apr 3 17:24:16 BST 2023 aarch64 GNU/Linux
  • Architecture | arm64
  • SBC model | RPi 4 Model B (aarch64)
  • Power supply used | (EG: 5V 1A RAVpower)
  • SD card used | SSD

I have been running this OS for a few days. It has made my life much easier.
I run my smartHome as Docker here.
However, I have noticed that the time deviates massively. After only a few moments, the time is outdated again.
I do not know now if this is related, but I use debian.pool.ntp.org as NTP Mirror. But even the Gateway option doesn’t work for me.

Here an extract from ‘journalctl -u systemd-timesyncd.service’:

-- Journal begins at Thu 2023-05-18 18:39:06 CEST, ends at Thu 2023-05-18 19:16:26 CEST. --
Mai 18 18:39:07 SmartHome systemd[1]: Starting Network Time Synchronization...
Mai 18 18:39:07 SmartHome systemd[1]: Started Network Time Synchronization.
Mai 18 18:41:11 SmartHome systemd-timesyncd[280]: Initial synchronization to time server 116.202.14.29:123 (2.debian.pool.ntp.org).
Mai 18 18:41:11 SmartHome systemd[1]: Stopping Network Time Synchronization...
Mai 18 18:41:11 SmartHome systemd[1]: systemd-timesyncd.service: Succeeded.
Mai 18 18:41:11 SmartHome systemd[1]: Stopped Network Time Synchronization.

I hope this helps. Would be very happy about a feedback or solution.

2

we have seen such behaviour if CPU frequency was set to a too low value. Can you share

cat /boot/config.txt
3 
# Docs: https://www.raspberrypi.com/documentation/computers/config_txt.html
# Overlays: https://github.com/raspberrypi/firmware/blob/b150147d0135e5ba4bed7e30cda8ff96ce7d92f8/boot/overlays/README

#-------Display---------
# Max allocated framebuffers: Set to "0" in headless mode to reduce memory usage
# - Defaults to "2" on RPi4 and "1" on earlier RPi models
max_framebuffers=0

# If you get no picture, set the following to "1" to apply most compatible HDMI settings.
#hdmi_safe=1

# Uncomment to adjust the HDMI signal strength if you have interferences, blanking, or no display.
# - Ranges from "0" to "11", use values above "7" only if required, e.g. with very long HDMI cable.
# - Default on first RPi1 A/B is "2", else "5", on RPi4 this setting is ignored.
#config_hdmi_boost=5

# Uncomment if HDMI display is not detected and composite is being outputted.
#hdmi_force_hotplug=1

# Uncomment to disable HDMI even if plugged, e.g. to force composite output.
hdmi_ignore_hotplug=1

# Uncomment to force a console size. By default it will be display's size minus overscan.
#framebuffer_width=1280
#framebuffer_height=720

# Uncomment to enable SDTV/composite output on RPi4. This has no effect on previous RPi models.
#enable_tvout=0
# SDTV mode
#sdtv_mode=0

# Uncomment to force a specific HDMI mode (this will force VGA).
#hdmi_group=1
#hdmi_mode=1

# Uncomment to force an HDMI mode rather than DVI. This enables HDMI audio in DMT modes.
#hdmi_drive=2

# Set "hdmi_blanking=1" to allow the display going into standby after 10 minutes without input.
# With default value "0", the display shows a blank screen instead, but will not go into standby.
# NB: Some legacy OpenMAX applications (OMXPlayer) cannot wake screens from real standby.
hdmi_blanking=1

# Set to "1" if your display has a black border of unused pixels visible.
disable_overscan=1

# Uncomment the following to adjust overscan.
# Use positive numbers if console goes off screen, and negative if there is too much border.
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# Rotation
#display_hdmi_rotate=0
#lcd_rotate=0

#-------RPi camera module-------
#start_x=1
#disable_camera_led=1

#-------GPU memory splits-------
gpu_mem_256=16
gpu_mem_512=16
gpu_mem_1024=16

#-------Boot splash screen------
disable_splash=1

#-------Onboard sound-----------
dtparam=audio=off

#-------I2C-------------
#dtparam=i2c_arm=off
#dtparam=i2c_arm_baudrate=100000

#-------SPI-------------
#dtparam=spi=off

#-------Serial/UART-----
# NB: "enable_uart=1" will enforce "core_freq=250" on RPi models with onboard WiFi.
enable_uart=0

#-------SD card HPD-----
# Comment to enable SD card hot-plug detection, while booting via USB or network.
# NB: This causes constant CPU load and kernel errors when no SD card is inserted.
dtparam=sd_poll_once

#-------Overclock-------
temp_limit=65
initial_turbo=20

over_voltage=4
arm_freq=1900
core_freq=600

#over_voltage_min=0
arm_freq_min=300
#core_freq_min=250
#sdram_freq_min=400
arm_64bit=1
dtoverlay=disable-wifi
4

This should be the culprit, I have the same problems on my RPi 4, when the frequency is below 600MHz.

5

Yes don’t set it below 600. Its know for RPI4 to not work correctly if min value has been set too low. I recommend to hash # the value and restart your system.

6

I changed it in the dietpi-config menu. Now it is

arm_freq_min=600

Looks good so far. Thanks for your help.
Is it planned to fix this issue in the near future ?

7

This has nothing to do with DietPi. It’s related to RPi device and how CPU frequency is working there. Maybe @MichaIng could be more specific on this. If I’m not mistaken it is a known limitation of RPi4.

8

It is actually a known limitation on most other RPi models, which is why on those the minimum frequency cannot be lowered below 600 MHz anymore: [Kernel5.4] Lowering arm_freq_min leads to system hang/crash · Issue #1431 · raspberrypi/firmware · GitHub

On RPi 4 this mostly works, but we saw it by times that also the RPi 4 becomes unstable. Depends on the individual chip, it seems: https://github.com/MichaIng/DietPi/issues/4455

9

Could you please elaborate? DietPi-Performance > Overclocking ? DietPi-Performance > Overclocking > CPU Governor ? Default values in a RPi3B are default and schedutil respectively. ondemand and conservative CPU Governor settings seems to set a mininum of 600, whichever is more suited for your SBC. Thank you in advance.

10

I think he’s talkin about dietpi-config > 4 : Advanced Options > ARM Idle Frequency: [600 MHz]

11

Exactly.
image

12

And you did reboot after changing it?

13

yes

14

Probably the issue is not the CPU frequency then. Could you test whether the same happens with performance governor?

15

I think there’s an misunderstanding. f
It works for me. Therefore, my post can actually be marked as “solved”. My answer was rather @derebo , who apparently also has the problem.