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Thread: Backlight Issues

  1. #1
    Join Date
    Jun 2012
    Beans
    35

    Arrow Backlight Issues

    Hi Please someone help me!!

    I have a toshiba u920t convertible ultrabook, im trying to get any linux distro to work on it. I have tried Fedora, Open Suse, and now Ubuntu 13.10. Each distro has had a similar problem with the screen backlight, it is permanently on max. the slider in poweroptions has no effect and the "Fn" buttons do not change brightness either, the os dose not even show the brightness indicator going up and down when using "fn" buttons, but weirdly the brightness down button puts the computer into standby! this happened in fedora too.

    I came across this webpage suggesting how to change brightness via terminal:

    http://linuxg.net/change-the-brightn...-command-line/

    I dont really know how to use terminal so I may have done something wrong but when i pasted:

    # echo 3 > /sys/class/backlight/acpi_video0/brightness

    into terminal absolutely nothing happens, not even a message comes up

    I even tried:

    echo 3 > /sys/class/backlight/acpi_video0/brightness

    i.e without the "#" just for the hell of it, and a message came up saying "permission denied

    I tried both of the above on my other ubuntu laptop where the brightness does work and the same thing happened so i guess im just typing the command wrong


    The only other things to mention are that the brightness works in windows 8, the ultrabook has an ambient light sensor which may be messing things up and I hate it anyway so i don't care if it doesn't work, and also when in Open Suse i navigated to the file:
    /sys/class/backlight/acpi_video0/brightness
    the value was set to 100 and i could not change it, but i cant find this file in ubuntu

    one last thing; as well as /sys/class/backlight/acpi_video0/brightness
    there were two other files something along the lines of:
    /sys/class/backlight/intel/brightness
    which was set to 0 i think

    and /sys/class/backlight/toshiba/brightness
    which was set to something random like 1470


    unfortunately i cant seem to find these files on ubuntu live usb and seeing as I deleted the open suse usb to make this ubuntu one I can't go back and check to see if i'm telling you the right things,


    please someone help me solve this problem, all I want to be able to do is turn the brightness Up and down as needed, I don't care if I have to do it through terminal for ever I just need a solution! I don't wanna be stuck with crappy windows 8 just because of one tiny issue.

    Thanks in advance
    Last edited by LinuxVirgin2000; October 22nd, 2013 at 11:21 PM.

  2. #2
    Join Date
    Jun 2005
    Location
    Toronto, Canada
    Beans
    Hidden!
    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: Backlight Issues!!!

    Lets get some detailed information about your system. Can you open a terminal window, type in the following commands, and post back the results:

    1. Your current kernel boot line:
    Code:
    cat /proc/cmdline
    2. Info about your video card(s):
    Code:
    lspci -k | grep -iA3 VGA
    3. Your current backlight interfaces and their values:
    Code:
    for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/actual_brightness; cat $i/max_brightness; done
    4. Your dmesg log file:
    Code:
    pastebinit /var/log/dmesg
    ...and post back the link that is generated.

    5. Your Xorg log file:
    Code:
    pastebinit /var/log/Xorg.0.log
    ...and post back the link that is generated.

    Note: if you get a message about pastebinit not being installed, you can install it via:
    Code:
    sudo apt-get install pastebinit
    EDIT: Can you also post back a listing of your kernel modules:
    Code:
    lsmod
    Last edited by Toz; October 23rd, 2013 at 12:59 AM.

  3. #3
    Join Date
    Jun 2012
    Beans
    35

    Re: Backlight Issues!!!

    Hi thnaks so much for replying, heres the info you requested


    1. current kernel boot line:
    Code:
    BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
    2. Info about video card(s):
    Code:
    00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
        Subsystem: Toshiba America Info Systems Device 0006
        Kernel driver in use: i915

    3. current backlight interfaces and their values:
    Code:
    /sys/class/backlight/acpi_video0
    100
    100
    100
    /sys/class/backlight/intel_backlight
    4542
    4542
    4542
    /sys/class/backlight/toshiba
    0
    0
    7

    4. dmesg log file:
    http://paste.ubuntu.com/6289559/


    5. Xorg log file:
    http://paste.ubuntu.com/6289579/

    6.kernel modules:
    Code:
    Module                  Size  Used by
    dm_crypt               22728  0 
    x86_pkg_temp_thermal    14162  0 
    intel_powerclamp       14705  0 
    coretemp               13435  0 
    kvm_intel             138538  0 
    kvm                   431315  1 kvm_intel
    crct10dif_pclmul       14289  0 
    crc32_pclmul           13113  0 
    ghash_clmulni_intel    13259  0 
    aesni_intel            55624  3 
    microread_mei          12811  0 
    aes_x86_64             17131  1 aesni_intel
    lrw                    13257  1 aesni_intel
    microread              13420  1 microread_mei
    gf128mul               14951  1 lrw
    mei_phy                13881  1 microread_mei
    glue_helper            13990  1 aesni_intel
    ablk_helper            13597  1 aesni_intel
    cryptd                 20329  3 ghash_clmulni_intel,aesni_intel,ablk_helper
    btusb                  28267  0 
    crc_ccitt              12707  1 microread
    arc4                   12608  2 
    hci                    44425  2 mei_phy,microread
    nfc                    94614  2 hci,microread
    snd_hda_codec_hdmi     41276  1 
    iwldvm                237440  0 
    joydev                 17377  0 
    snd_hda_codec_realtek    51465  1 
    mac80211              596969  1 iwldvm
    snd_hda_intel          48171  3 
    snd_hda_codec         188738  3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel
    uvcvideo               80885  0 
    snd_hwdep              13602  1 snd_hda_codec
    dm_multipath           22843  0 
    snd_pcm               102033  3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
    iwlwifi               165398  1 iwldvm
    cp210x                 23475  0 
    videobuf2_vmalloc      13216  1 uvcvideo
    videobuf2_memops       13362  1 videobuf2_vmalloc
    videobuf2_core         40469  1 uvcvideo
    videodev              133390  2 uvcvideo,videobuf2_core
    scsi_dh                14882  1 dm_multipath
    usbserial              44667  1 cp210x
    rts5139               331166  0 
    snd_page_alloc         18710  2 snd_pcm,snd_hda_intel
    snd_seq_midi           13324  0 
    cfg80211              479757  3 iwlwifi,mac80211,iwldvm
    hid_sensor_hub         19096  0 
    snd_seq_midi_event     14899  1 snd_seq_midi
    hid_multitouch         17407  0 
    snd_rawmidi            30095  1 snd_seq_midi
    snd_seq                61560  2 snd_seq_midi_event,snd_seq_midi
    snd_seq_device         14497  3 snd_seq,snd_rawmidi,snd_seq_midi
    snd_timer              29433  2 snd_pcm,snd_seq
    snd                    69141  17 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq_device,snd_seq_midi
    microcode              23518  0 
    soundcore              12680  1 snd
    toshiba_acpi           22901  0 
    sparse_keymap          13948  1 toshiba_acpi
    wmi                    19070  1 toshiba_acpi
    mei_me                 18421  0 
    psmouse                97626  0 
    toshiba_bluetooth      12852  0 
    mei                    77692  3 mei_phy,mei_me,microread_mei
    lpc_ich                21080  0 
    bnep                   19564  2 
    parport_pc             32701  0 
    rfcomm                 69070  12 
    ppdev                  17671  0 
    intel_rst              12953  0 
    lp                     17759  0 
    serio_raw              13413  0 
    mac_hid                13205  0 
    parport                42299  3 lp,ppdev,parport_pc
    bluetooth             371874  22 bnep,btusb,rfcomm
    squashfs               47663  1 
    overlayfs              27858  1 
    nls_iso8859_1          12713  1 
    hid_generic            12548  0 
    usbhid                 53014  0 
    hid                   101512  4 hid_multitouch,hid_generic,hid_sensor_hub,usbhid
    dm_mirror              22056  0 
    dm_region_hash         20784  1 dm_mirror
    dm_log                 18411  2 dm_region_hash,dm_mirror
    usb_storage            62062  1 
    i915                  655752  3 
    i2c_algo_bit           13413  1 i915
    drm_kms_helper         52651  1 i915
    drm                   296739  4 i915,drm_kms_helper
    ahci                   25819  0 
    libahci                31898  1 ahci
    video                  19318  1 i915
    Last edited by Toz; October 23rd, 2013 at 07:58 PM. Reason: added code tags

  4. #4
    Join Date
    Jun 2005
    Location
    Toronto, Canada
    Beans
    Hidden!
    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: Backlight Issues!!!

    Quote Originally Posted by LinuxVirgin2000 View Post
    1. current kernel boot line:
    Code:
    BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
    How is ubuntu installed on your computer? Are you running the live cd?

    3. current backlight interfaces and their values:
    Code:
    /sys/class/backlight/acpi_video0
    100
    100
    100
    /sys/class/backlight/intel_backlight
    4542
    4542
    4542
    /sys/class/backlight/toshiba
    0
    0
    7
    You have 3 current backlight interfaces. I would suggest blacklisting the toshiba_acpi module and forcing the use of the intel_backlight interface. Here is how:
    1. Blacklisting toshiba_acpi:
    Code:
    sudo -i gedit /etc/modprobe.d/blacklist
    ...enter your password when prompted and add the following line to the end of the file:
    Code:
    blacklist toshiba_acpi
    ...and save the file.

    2. Force the use of the intel_backlight interface:
    Code:
    sudo -i gedit  /usr/share/X11/xorg.conf.d/20-intel.conf
    and copy/paste the following code:
    Code:
    Section "Device"
            Identifier  "card0"
            Driver      "intel"
            Option      "Backlight"  "intel_backlight"
            BusID       "PCI:0:2:0"
    EndSection
    ...save the file.

    3. Reboot and test.

    If it still doesn't work, post back the same information again as per post #2.

  5. #5
    Join Date
    Jun 2012
    Beans
    35

    Re: Backlight Issues

    Hi, I tried the above but it won't work anyway because im running ubuntu from a live USB because i need to find an OS that works before I install it, when I was making the Live USB (using startup disk creator on my other ubuntu 12.04 laptop) the slider to select how much space to preserve for storage was grayed out, so when i have to reboot the machine as your instructions above ask all the changes are being lost I guess. The weird thing is that when i try to make a 12.04 live USB it allows me to make the USB persistent but for 13.10 it dosent let me. I would happily just use 12.04 but its refusing to boot on my ultrabook (i think its something to do with secure boot)

  6. #6
    Join Date
    Jun 2012
    Beans
    35

    Re: Backlight Issues

    Hi Toz, i finally managed to make my live USB persistent with the kind help of people on this forum and I used your suggestion above and it works great!!!! I can't change the brightness using the Fn buttons still but atleast it can change using the slider in brightness settings. thank you very much

  7. #7
    Join Date
    Nov 2013
    Beans
    1

    Re: Backlight Issues!!!

    2. Force the use of the intel_backlight interface:
    Code:
    sudo -i gedit  /usr/share/X11/xorg.conf.d/20-intel.conf
    and copy/paste the following code:
    Code:
    Section "Device"
            Identifier  "card0"
            Driver      "intel"
            Option      "Backlight"  "intel_backlight"
            BusID       "PCI:0:2:0"
    EndSection
    ...save the file.

    3. Reboot and test.

    If it still doesn't work, post back the same information again as per post #2.[/QUOTE]




    I've been experiencing the same issue since I installed Ubuntu about a year ago. Ran only this part, and now it works like a charm. Thanks a ton!

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