AVL 23.1: issue with backlight [Solved]

[seriousness]

Hi there,

booting with acpi_backlight=native is the only way to get screen brightness control working on my Samsung RV520.

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System:
  Kernel: 6.6.9-1-liquorix-amd64 [6.6-11~mx23ahs] arch: x86_64 bits: 64 compiler: gcc v: 12.2.0 parameters: audit=0
    intel_pstate=disable rcupdate.rcu_expedited=1 BOOT_IMAGE=/boot/vmlinuz-6.6.9-1-liquorix-amd64
    root=UUID=<filter> ro threadirqs quiet acpi_backlight=native init=/lib/systemd/systemd
  Desktop: Enlightenment v: 0.25.4 vt: 7 dm: LightDM v: 1.26.0 Distro: AVL_MXE-23.1-20240120_x64
    Enlightened January 15 2024 base: Debian GNU/Linux 12 (bookworm)
Machine:
  Type: Laptop System: SAMSUNG product: RV420/RV520/RV720/E3530/S3530/E3420/E3520 v: 0.1
    serial: <superuser required> Chassis: type: 9 v: 0.1 serial: <superuser required>
  Mobo: SAMSUNG model: RV420/RV520/RV720/E3530/S3530/E3420/E3520 v: FAB1
    serial: <superuser required> UEFI-[Legacy]: Phoenix v: 03PQ date: 07/08/2011
Battery:
  ID-1: BAT1 charge: 32.0 Wh (80.0%) condition: 40.0/48.8 Wh (81.8%) volts: 10.7 min: 11.1
    model: SAMSUNG Electronics type: Li-ion serial: N/A status: not charging
CPU:
  Info: model: Intel Core i5-2410M bits: 64 type: MT MCP arch: Sandy Bridge gen: core 2 level: v2
    built: 2010-12 process: Intel 32nm family: 6 model-id: 0x2A (42) stepping: 7 microcode: 0x2F
  Topology: cpus: 1x cores: 2 tpc: 2 threads: 4 smt: enabled cache: L1: 128 KiB
    desc: d-2x32 KiB; i-2x32 KiB L2: 512 KiB desc: 2x256 KiB L3: 3 MiB desc: 1x3 MiB
  Speed (MHz): avg: 2623 high: 2694 min/max: 800/2301 boost: enabled scaling:
    driver: acpi-cpufreq governor: ondemand cores: 1: 2411 2: 2694 3: 2694 4: 2693 bogomips: 18358
  Flags: avx ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
  Vulnerabilities:
  Type: gather_data_sampling status: Not affected
  Type: itlb_multihit status: KVM: VMX disabled
  Type: l1tf mitigation: PTE Inversion; VMX: conditional cache flushes, SMT vulnerable
  Type: mds mitigation: Clear CPU buffers; SMT vulnerable
  Type: meltdown mitigation: PTI
  Type: mmio_stale_data status: Unknown: No mitigations
  Type: retbleed status: Not affected
  Type: spec_rstack_overflow status: Not affected
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via prctl
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization
  Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, IBRS_FW, STIBP: conditional, RSB
    filling, PBRSB-eIBRS: Not affected
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: NVIDIA GF119M [GeForce GT 520M] vendor: Samsung Co driver: nouveau v: kernel non-free:
    series: 390.xx+ status: legacy-active (EOL~late 2022) arch: Fermi code: GF1xx process: 40/28nm
    built: 2010-16 pcie: gen: 1 speed: 2.5 GT/s lanes: 16 ports: active: LVDS-1
    empty: HDMI-A-1,VGA-1 bus-ID: 01:00.0 chip-ID: 10de:1050 class-ID: 0300 temp: 66.0 C
  Device-2: Silicon Motion WebCam SC-0311139N type: USB driver: uvcvideo bus-ID: 1-1.4:3
    chip-ID: 2232:1020 class-ID: 0e02 serial: <filter>
  Display: x11 server: X.Org v: 1.21.1.7 compositor: enlightenment driver: X: loaded: modesetting
    unloaded: fbdev,vesa dri: nouveau gpu: nouveau display-ID: :0.0 screens: 1
  Screen-1: 0 s-res: 1366x768 s-dpi: 96 s-size: 361x203mm (14.21x7.99") s-diag: 414mm (16.31")
  Monitor-1: LVDS-1 model: Seiko Epson 0x5441 built: 2011 res: 1366x768 hz: 60 dpi: 101
    gamma: 1.2 size: 344x194mm (13.54x7.64") diag: 395mm (15.5") ratio: 16:9 modes: max: 1366x768
    min: 640x350
  API: OpenGL v: 4.3 Mesa 23.1.2-1~mx23ahs renderer: NVD9 direct-render: Yes
Audio:
  Device-1: Intel 6 Series/C200 Series Family High Definition Audio vendor: Samsung Co 6
    driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:1c20 class-ID: 0403
  Device-2: NVIDIA GF119 HDMI Audio vendor: Samsung Co driver: snd_hda_intel v: kernel pcie:
    gen: 1 speed: 2.5 GT/s lanes: 16 bus-ID: 01:00.1 chip-ID: 10de:0e08 class-ID: 0403
  API: ALSA v: k6.6.9-1-liquorix-amd64 status: kernel-api tools: alsamixer,amixer
  Server-1: PipeWire v: 1.0.0 status: active with: 1: pipewire-pulse status: active
    2: wireplumber status: active 3: pipewire-alsa type: plugin 4: pw-jack type: plugin
    tools: pactl,pw-cat,pw-cli,wpctl
Network:
  Device-1: Qualcomm Atheros AR9285 Wireless Network Adapter vendor: Samsung Co driver: ath9k
    v: kernel modules: wl pcie: gen: 1 speed: 2.5 GT/s lanes: 1 bus-ID: 02:00.0 chip-ID: 168c:002b
    class-ID: 0280
  IF: wlp2s0 state: up mac: <filter>
  Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Samsung Co
    driver: r8169 v: kernel pcie: gen: 1 speed: 2.5 GT/s lanes: 1 port: 2000 bus-ID: 03:00.0
    chip-ID: 10ec:8168 class-ID: 0200
  IF: enp3s0 state: down mac: <filter>
Drives:
  Local Storage: total: 465.76 GiB used: 15.12 GiB (3.2%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/sda maj-min: 8:0 vendor: Samsung model: HN-M500MBB size: 465.76 GiB block-size:
    physical: 4096 B logical: 512 B speed: 3.0 Gb/s type: HDD rpm: 5400 serial: <filter> rev: 0001
    scheme: MBR
Partition:
  ID-1: / raw-size: 36 GiB size: 35.14 GiB (97.61%) used: 14.06 GiB (40.0%) fs: ext4 dev: /dev/sda7
    maj-min: 8:7
  ID-2: /home raw-size: 80 GiB size: 78.19 GiB (97.74%) used: 1006 MiB (1.3%) fs: ext4
    dev: /dev/sda8 maj-min: 8:8
Swap:
  Kernel: swappiness: 10 (default 60) cache-pressure: 100 (default)
  ID-1: swap-1 type: partition size: 9 GiB used: 0 KiB (0.0%) priority: -2 dev: /dev/sda6
    maj-min: 8:6
Sensors:
  System Temperatures: cpu: 75.0 C mobo: N/A gpu: nouveau temp: 66.0 C
  Fan Speeds (RPM): N/A
Repos:
  Packages: pm: dpkg pkgs: 2388 libs: 1402 tools: apt,apt-get,aptitude,synaptic pm: rpm pkgs: 0
    pm: flatpak pkgs: 0
  No active apt repos in: /etc/apt/sources.list
  Active apt repos in: /etc/apt/sources.list.d/debian-stable-updates.list
    1: deb http://deb.debian.org/debian bookworm-updates main contrib non-free non-free-firmware
  Active apt repos in: /etc/apt/sources.list.d/debian.list
    1: deb http://deb.debian.org/debian bookworm main contrib non-free non-free-firmware
    2: deb http://security.debian.org/debian-security bookworm-security main contrib non-free non-free-firmware
  Active apt repos in: /etc/apt/sources.list.d/mx.list
    1: deb http://mxrepo.com/mx/repo/ bookworm main non-free
    2: deb http://mxrepo.com/mx/repo/ bookworm ahs
Info:
  Processes: 291 Uptime: 25m wakeups: 1 Memory: 5.78 GiB used: 1.05 GiB (18.2%) Init: systemd
  v: 252 target: graphical (5) default: graphical tool: systemctl Compilers: gcc: 12.2.0 alt: 12
  Client: shell wrapper v: 5.2.15-release inxi: 3.3.26
Boot Mode: BIOS (legacy, CSM, MBR)

During the boot process, the screen gets black (with init) respectively dark (with systemd).
After logging in, everything works fine.
Somewhere in the internet I read that the /sys/class/backlight/ mechanism has been refurbished and one should remove all acpi_backlight=* boot options...

A workaround could be using software (xrandr) brightness in MX Tweaks, which is not available in AVL 32.1 .

[AVLinux]

So lightdm is displaying dark but the desktop session is fine?

I had a similar issue pop up installing on my son's Thinkpad but booting systemd fixed it, systemd doesn't work in your case?

[seriousness]

Hello Glen,

I read your post, just did not want to append to this quite long thread.

With systemd, lightdm greeter is visible, but quite dark. With init, it's black and I have to log in blindly.

[AVLinux]

Hello Glen,

I read your post, just did not want to append to this quite long thread.

With systemd, lightdm greeter is visible, but quite dark. With init, it's black and I have to log in blindly.

Thanks for posting a solution, there is also a backlight module in Enlightenment which is shut off by default but I am not sure if it addresses anything that is outside of the Enlightenment session itself..

shot-2024-02-16_13-25-20.jpg

[Charlie Brown]

... acpi_backlight=native is the only way ...

Just to make sure: You also tried others? =video especially ? Normally it should keep the last level.

If still not:

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cat /sys/class/backlight/acpi_video0/max_brightness

(Just to make sure, it's 10 here.)

Then, i.e.

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sudo sed -i '/^exit 0/iecho 6 > /sys/class/backlight/acpi_video0/brightness' /etc/rc.local

Reboot.


... Or (alternatively) for 50% just:

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sudo sed -i '/^exit 0/iecho $(($(cat /sys/class/backlight/acpi_video0/max_brightness)/2)) > /sys/class/backlight/acpi_video0/brightness' /etc/rc.local

Reboot.

[seriousness]

Hello Charles,

yes, I tried the other options.

acpi_backlight=video (which does the same as no option) worked in AVL 21.3, but with only 8 steps.

acpi_backlight=native gives /sys/class/backlight/nv_backlight with values from 0 - 100 .

After login my brightness value is restored, so that's not the problem.

[Charlie Brown]

Ok. I just mean if you insert the desired value (say 60) into /etc/rc.local before the last (exit 0) line it'll take effect even before login (just for you say login screen is dark)..

You can manually "edit as root" and add i.e.

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echo 60 > /sys/class/backlight/.../whatever-the-file-is

[seriousness]

Thanks for this workaround, Charlie Brown!

This helps until someone is able to fix, whatever sets these unusable brightness values during boot.

[AVLinux]

Hi,

It will be difficult to effectively 'fix' on my end as it only affects certain systems and if I start putting 'just in case' boot codes or scripts in rc.local then it may potentially negatively affect other systems..

@dolphin_oracle is there something you guys are doing in regular MX installs to mitigate backlight issues? If so I should probably roll it into the AVL default build...

@Charlie Brown sincere thanks for your expertise with these questions, very much appreciated!

[Charlie Brown]

@AVLinux You're always welcome, you make me shy, I'm a shy cowboy