Screen is hardly readable

Forum Forums General Hardware Screen is hardly readable

  • This topic has 16 replies, 8 voices, and was last updated Jul 4-4:19 pm by bertram.
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  • #109923

      on a 20 years old Cytron TCM-Laptop (32-bit) I installed antix-Linux. It worked. But the screen is hardly readable, very dark (it works better, when I use an external light from above). The laptop does not respond to the function keys to increase the screen brightness.

      here some information about Hardware (input hardinfo)

      Prozessor    Intel(R) Celeron(R) M processor 1.30GHz
      Hauptspeicher    439MB (159MB used)
      Maschinen-Typ    Unknown chassis type
      Betriebssystem    Debian GNU/Linux 11 (bullseye)
      Benutzername    antix (Unknown)
      Date/Time    Sa 24 Jun 2023 16:49:54 CEST
      Auflösung    1024x768 pixels
      OpenGL-Renderer    llvmpipe (LLVM 11.0.1, 128 bits)
      X11-Hersteller    The X.Org Foundation
      Audio Adapter    VIA8233 - VIA 8235
      Audio Adapter    VIA82XX-MODEM - VIA 82XX modem
      AT Translated Set 2 keyboard    
      ImPS/2 Elantech Touchpad    
      Power Button    
      Sleep Button    
      Lid Switch    
      Power Button    
      Video Bus
      Kernel    Linux 4.9.0-326-antix.1-486-smp (i686)
      Version    #2 SMP Fri Aug 26 18:47:43 EDT 2022
      C-Library    GNU C Library / (Debian GLIBC 2.31-13+deb11u6) 2.31
      Distribution    Debian GNU/Linux 11 (bullseye)
      Aktuelle Sitzung
      Computername    antix1
      Benutzername    antix (Unknown)
      Sprache    de_DE.UTF-8 (de_DE.UTF-8)
      Stammverzeichnis    /home/antix
      Uptime    59 Minuten
      Load Average    0,29, 0,38, 0,38
      Available entropy in /dev/random    256 bits (medium)
      Geladene Module
      hfsplus    Extended Macintosh Filesystem
      jfs    The Journaled Filesystem (JFS)
      xfs    SGI XFS with ACLs, security attributes, realtime, no debug enabled
      libcrc32c    CRC32c (Castagnoli) calculations
      llc    LLC IEEE 802.2 core support
      lockd    NFS file locking service version 0.5.
      fscache    FS Cache Manager
      dm_crypt    device-mapper target for transparent encryption / decryption
      dm_mod    device-mapper driver
      via_ircc    VIA IrDA Device Driver
      snd_via82xx    VIA VT82xx audio
      snd_mpu401_uart    Routines for control of MPU-401 in UART mode
      gameport    Generic gameport layer
      evdev    Input driver event char devices
      snd_rawmidi    Midlevel RawMidi code for ALSA.
      snd_via82xx_modem    VIA VT82xx modem
      input_leds    Input -> LEDs Bridge
      snd_seq_device    ALSA sequencer device management
      snd_ac97_codec    Universal interface for Audio Codec '97
      serio_raw    Raw serio driver
      snd_pcm    Midlevel PCM code for ALSA.
      snd_timer    ALSA timer interface
      snd    Advanced Linux Sound Architecture driver for soundcards.
      soundcore    Core sound module
      irda    The Linux IrDA Protocol Stack
      pcmcia    PCMCIA Driver Services
      pcmcia_core    Linux Kernel Card Services
      shpchp    Standard Hot Plug PCI Controller Driver
      battery    ACPI Battery Driver
      video    ACPI Video Driver
      ac    ACPI AC Adapter Driver
      button    ACPI Button Driver
      raid6_pq    RAID6 Q-syndrome calculations
      psmouse    PS/2 mouse driver
      via_rhine    VIA Rhine PCI Fast Ethernet driver
      mii    MII hardware support library
      i2c_viapro    vt82c596 SMBus driver
      thermal    ACPI Thermal Zone Driver
      fjes    FUJITSU Extended Socket Network Device Driver
      rtc_cmos    Driver for PC-style 'CMOS' RTCs
      Auflösung    1024x768 pixels
      Hersteller    The X.Org Foundation
      Version    1.20.11
      Current Display Name    :0.0
      Bildschirm 0    1024x768 Pixel
      Hersteller    Mesa/
      Renderer    llvmpipe (LLVM 11.0.1, 128 bits)
      Version    3.1 Mesa 20.3.5
      Direct-Rendering    Ja

      What can I do?

      • This topic was modified 8 months, 1 week ago by bertram.

        Does another OS have the same results? I’m wondering if the hardware is failing.
        Try control centre > hardware > backlight brightness.
        Also, did you try to adjust the bios to set the screen brightness at 100%?

        • This reply was modified 8 months, 1 week ago by christophe.

        confirmed antiX frugaler, since 2019


          You have not told screen output, but basically you can set baclight brigtness via Terminal like

          xrandr -q | grep " connected"

          … tells your screen

          xrandr --output LVDS --brightness 1

          … set brigtness 1 if the screen is LVDS


          You can set backlight using command


          • This reply was modified 8 months, 1 week ago by RJP.
          • This reply was modified 8 months, 1 week ago by RJP.

            the problem was the same with windows XP, the former system on this laptop. The laptop has not been used for many years. I do not know how to change brightness in BIOS – because of the weak brightness, it is difficult to read. I just changed the bios preferences to “default”, but nothing changed.

            the control center – hardware has no option “backlight-brightness” (only sound, mouse, PC-Information)

            PC information tells me about graphics: lspci -vnn | grep VGA -A12

            When I put this command in terminal lspci -vnn | grep VGA -A12
            I get
            01:00.0 VGA compatible controller [0300] VGA technologies CN400/PM800/PM8
            PN800/PN880 [S3 UniChrome Pro] [1106:3118] (rev02) (prog-if 00 [VGA controller]
            and some more information I hardly can read (because of darkness), but nothing about “brightness”

            • This reply was modified 8 months, 1 week ago by bertram.
            • This reply was modified 8 months, 1 week ago by bertram.
            • This reply was modified 8 months, 1 week ago by bertram.

              when I use the terminal with
              <xrandr -q | grep ” connected”> I get
              <failed to get size of gamma for output default
              default connected 1024×768+0+0 0mm x 0mm>

              when I input <backlight-brightness>
              I get <did not find a controller>

              Lead Farmer

                As @RJP said use backlight-brightness command with + or – and a number, try:

                backlight-brightness +50

                Or set the brightness

                backlight-brightness -s 100

                backlight-brightness help

                backlight-brightness --help

                • This reply was modified 8 months, 1 week ago by Lead Farmer.
                • This reply was modified 8 months, 1 week ago by Lead Farmer.

                  Renderer llvmpipe

                  Your graphic driver isn’t installed properly or you are using the vesa driver.Please post
                  inxi -Gxxx


                    Hi bertram,

                    You wrote that you have the same problem with linux and with windows.

                    That suggests it is a hardware issue.

                    Can you attach an external monitor and check if the brightness is good on that screen?



                      thanks for your ideas!
                      @stevesr0: I tried with an external monitor – there the brightness is ok.
                      @caprea: here the result of inxi -Gxxx

                      $ inxi -Gxxx
                        Device-1: VIA CN400/PM800/PM880/PN800/PN880 [S3 UniChrome Pro]
                          vendor: CLEVO/KAPOK driver: N/A bus-ID: 01:00.0 chip-ID: 1106:3118
                          class-ID: 0300
                        Display: server: X.Org v: 1.20.11 driver: X: loaded: vesa dri: swrast
                          gpu: N/A display-ID: :0.0 screens: 1
                        Screen-1: 0 s-res: 640x480 s-dpi: 43 s-size: 382x302mm (15.04x11.89")
                          s-diag: 487mm (19.17")
                        Monitor-1: default res: 640x480 size: N/A modes: N/A
                        API: OpenGL v: 4.5 Mesa 20.3.5 renderer: llvmpipe (LLVM 11.0.1 128 bits)
                          compat-v: 3.1 direct-render: Yes

                      is it possible, that with changed graphic driver it could work? How can I update them?


                        How about if you install xserver-xorg-video-openchrome and openchrome-tool packages?


                        • This reply was modified 8 months, 1 week ago by RJP.

                          is it possible, that with changed graphic driver it could work?

                          Display: server: X.Org v: 1.20.11 driver: X: loaded: vesa

                          At least with the vesa driver, which is used on your system, the backlight-brightness tool will not work anyway, afaik.
                          Your video card should use the openchrome driver.Example see this post from seaken64, it’s the same card,same antiX system and same kernel but the openchrome driver is used here.
                          Display: server: X.Org v: 1.20.11 driver: X: loaded: openchrome
                          Did you boot the live stick with any boot parameter like save video or failsave, before installation?This could be a reason for vesa.
                          On the other hand it’s might a hardware problem anyway if the brightness works on the external monitor.
                          But the vesa driver is always a last resort, it is a stopgap solution when nothing else works.


                            This works on my old netbook, so it’s worth a try. In the terminal:

                            $ ls /sys/class/backlight
                            $ cat /sys/class/backlight/acpi_video0/max_brightness
                            echo 8 > /sys/class/backlight/acpi_video0/brightness  

                            The name of your backlight device and the value of max_brightness will probably be different. You might have to use echo (number) | sudo tee /sys etc.


                              Hi bertram,

                              WARNING: I am offering this as a very NONexpert. I just read the thread and looked up some pages on the Web that deal with this complaint.

                              If the screen is too dim with both Windows and Linux OSes AND an external monitor is bright, then to my eyes, this indicates/suggests a HARDWARE issue with the laptop display.

                              For example, the inverter that controls the “backlight” which determines the brightness of the screen.

                              A problem in the BIOS settings might cause this in all operating systems.

                              A test of whether it might be BIOS related or hardware is to enter the BIOS screen and see if the brightness there is normal or dim. If it is bright there, that indicates a BIOS issue; either a configuration problem or a need for an update (if available).

                              If it is dim in the BIOS, that again points to a hardware issue which would require repair.



                                Hi stevesr0,
                                now I tried, if the light is working in BIOS.
                                It is strange: when I start the cold laptop, in the beginning I see for ca. 1 second the start screen of intel (look at the picture). After 1 second the screen becomes dark. Also if I look at BIOS the screen keeps dark (I can only read it with an external light).

                                Does that mean, that it has nothing to do with drivers? But why is the light ok in the first second of booting?


                                  Hi Bertram,

                                  I am NOT very knowledgeable about (any of) this “stuff”.

                                  My only thought is to check (using external lighting) if there is a BIOS setting for screen brightness. If so AND it can be increased, I would increase it to check if the screen brightens.

                                  If there is a setting and it is at a maximum already, then I assume that the hardware needs a fix (backlight inverter might need to be repaired or replaced, for example).

                                  Beyond that I can’t think of anything else to solve the screen problem.

                                  Good luck.


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