[Bug 2015628] New: No entry /sys/class/leds for Fn 5 key that toggles keyboard backlight

https://bugzilla.redhat.com/show_bug.cgi?id=2015628

            Bug ID: 2015628
           Summary: No entry /sys/class/leds for Fn 5 key that toggles
                    keyboard backlight
           Product: Fedora
           Version: 34
          Hardware: x86_64
                OS: Linux
            Status: NEW
         Component: xkeyboard-config
          Severity: medium
          Assignee: peter.hutterer(a)redhat.com
          Reporter: eb30750(a)gmail.com
        QA Contact: extras-qa(a)fedoraproject.org
                CC: ajax(a)redhat.com, caillon+fedoraproject(a)gmail.com,
                    i18n-bugs(a)lists.fedoraproject.org,
                    negativo17(a)gmail.com, peter.hutterer(a)redhat.com,
                    rhughes(a)redhat.com, rstrode(a)redhat.com,
                    sandmann(a)redhat.com
  Target Milestone: ---
    Classification: Fedora



Description of problem: Keyboard backlight worked until upgrading to FC34.  The
Fn 5 key toggled the keyboard backlight on and off.  In researching the new
method to expose the Fn keys to the user I found that there is no input/input5.


The input/input3 is configured.  

lrwxrwxrwx  1 root root 0 Jul 10 16:30 input3::capslock ->
../../devices/platform/i8042/serio0/input/input3/input3::capslock
lrwxrwxrwx  1 root root 0 Jul 10 16:30 input3::numlock ->
../../devices/platform/i8042/serio0/input/input3/input3::numlock
lrwxrwxrwx  1 root root 0 Jul 10 16:30 input3::scrolllock ->
../../devices/platform/i8042/serio0/input/input3/input3::scrolllock
lrwxrwxrwx  1 root root 0 Jul 10 16:30 phy0-led ->
../../devices/pci0000:00/0000:00:1c.0/0000:01:00.0/leds/phy0-led


Version-Release number of selected component (if applicable):

5.14.11-200.fc34.x86_64

How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:


Expected results:
A script or kernel option that builds the /sys/class/leds/input/input5
hierarchy.

Additional info:
If the input5 exists then simply changing the brightness value should turn on
the keyboard backlight.


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[Bug 2015628] No entry /sys/class/leds for Fn 5 key that toggles keyboard backlight

https://bugzilla.redhat.com/show_bug.cgi?id=2015628

Paul Lambert <eb30750(a)gmail.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|xkeyboard-config            |xorg-x11-drv-amdgpu
                 CC|                            |atherchris(a)gmail.com



--- Comment #1 from Paul Lambert <eb30750(a)gmail.com&gt; ---

I found that my laptop uses the backlight class as in
/sys/class/backlight/amdgpu_bl0. 

This is the systemctl output:
systemctl status systemd-backlight@backlight
○ systemd-backlight(a)backlight.service - Load/Save Screen Backlight Brightness
of backlight
     Loaded: loaded (/usr/lib/systemd/system/systemd-backlight@.service;
static)
     Active: inactive (dead)
       Docs: man:systemd-backlight@.service(8)

It appears that there are a couple of issues.

1)  The brigthness numbers get converted to 5 digits instead of 3 which is not
valid.  
https://bugzilla.kernel.org/show_bug.cgi?id=203905

2) There is a bug in the admgpu kernel driver that enables it even if the
backlight device is controlled by AUX.  
https://unix.stackexchange.com/questions/616371/backlight-control-not-wor...

#1 is a kernel fix and it might be quite awhile before this gets fixed.  Are
there any workarounds?


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[Bug 2015628] No entry /sys/class/leds for Fn 5 key that toggles keyboard backlight

https://bugzilla.redhat.com/show_bug.cgi?id=2015628



--- Comment #2 from Paul Lambert <eb30750(a)gmail.com&gt; ---
I found this kernel patch (below) that addressed the keyboard backlight.  It
was developed in 3rd qtr of 2020 for Asus.  It was just included in the Asus
5.14.9 kernel release only a couple of weeks ago. I am using kernel 5.14.11
fc34.  I can only assume this patch is yet to make its way into Fedora.  

https://lab.retarded.farm/zappel/asus-rog-zephyrus-g14/-/raw/master/kerne...


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[Bug 2015628] No entry /sys/class/leds for Fn 5 key that toggles keyboard backlight

https://bugzilla.redhat.com/show_bug.cgi?id=2015628

Parag Nemade <pnemade(a)redhat.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|i18n-bugs(a)lists.fedoraproje |
                   |ct.org                      |
           Doc Type|---                         |If docs needed, set a value




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