Am 20.07.25 um 01:39 schrieb Nikita Krasnov:

Hello!

I have a Xiaomi RedmiBook Pro 16 laptop and I suspect it is missing a
driver.

The laptop has a top row of F1-F12 buttons that can also control volume,
brightness and many other things. Most of them work fine and produce a
completely valid output (shown via `acpi_listen` from the `acpid`
package):

   button/mute MUTE 00000080 00000000
   button/volumedown VOLDN 00000080 00000000
   button/volumeup VOLUP 00000080 00000000
   video/brightnessdown BRTDN 00000087 00000000
   video/brightnessup BRTUP 00000086 00000000

But then there is a "Mute mic" key (F4 button with an image of a
crossed-out microphone). It has an LED that lights up and down when the
button is being pressed, but there is no keycode, no dmesg message and
no _valid_ ACPI event — the message in `acpi_listen` is always the same,
no matter the state of the button. Pressing the button multiple times
produces the same output:

   wmi PNP0C14:00 00000020 00000000

Might be a good time to mention that I nave 0 experience with ACPI, WMI
and drivers in general... I tried debugging the issue further and got
some data, but I lack the proper knowledge to interpret it.

Running `acpidump -b` (from `acpica-tools` package) generated some .dat
files which I then decompiled with `iasl -d` (from the same
`acpica-tools` package).

   # acpidump -b
   # iasl -d dsdt.dat

The resulting `dsdt.dsl` file has some code that mentions "PNP0C14".
I've attached this file with this email.

Hi,

please share the whole output of acpidump as the DSDT contains only two unrelated
WMI devices.

I also tried restarting the kernel with this configuration (NixOS
shenanigans; not sure what exactly it does there), but that didn't seem
to produce any extra files or directories on the system (in /sys and
/dev).

   boot.initrd.availableKernelModules = [
     "xhci_pci"
     "thunderbolt"
     "nvme"
     "usb_storage"
     "sd_mod"
   ];
   boot.initrd.kernelModules = [ ];
   boot.kernelModules = [ "kvm-intel" "wmi-sysfs" "wmi" "acpi_call" ];
   boot.extraModulePackages = [ ];

Those additional modules will likely not help you, i suspect that we need
to extend the xiaomi-wmi driver a bit to add support for additional keyboard
events.

Here is some extra info that might be relevant:

   $ ls /dev/wmi
   ls: cannot access '/dev/wmi': No such file or directory

   $ ls -1 /sys/bus/wmi/devices
   05901221-D566-11D1-B2F0-00A0C9062910
   05901221-D566-11D1-B2F0-00A0C9062910-1
   05901221-D566-11D1-B2F0-00A0C9062910-2
   05901221-D566-11D1-B2F0-00A0C9062910-3
   1DCEAF0A-4D63-44BB-BD0C-0D6281BFDDC5
   1F13AB7F-6220-4210-8F8E-8BB5E71EE969
   2BC49DEF-7B15-4F05-8BB7-EE37B9547C0B
   3F9E3C26-B077-4F86-91F5-37FF64D8C7ED
   46C93E13-EE9B-4262-8488-563BCA757FEF
   657B6048-310C-4A90-A211-10A17922A0AF
   A6FEA33E-DABF-46F5-BFC8-460D961BEC9F
   B60BFB48-3E5B-49E4-A0E9-8CFFE1B3434B
   F80A5498-23F3-4053-A244-B39067EC476F
   FA78E245-2C0F-4CA1-91CF-15F34E474850

   $ ls /sys/bus/wmi/devices/2BC49DEF-7B15-4F05-8BB7-EE37B9547C0B/
   driver_override  expensive  guid  instance_count
   modalias  object_id  power  subsystem  uevent

   $ uname -a
   Linux 6.15.5 #1-NixOS SMP PREEMPT_DYNAMIC x86_64 GNU/Linux
   
   $ ls /proc/acpi
   button  wakeup

   $ sudo cat /proc/acpi/button/lid/LID0/state
   state:      open

   $ sudo cat /proc/acpi/wakeup
   Device    S-state    Status     Sysfs node
   AWAC      S4         *enabled   platform:ACPI000E:00
   XDCI      S4         *disabled
   XHCI      S4         *enabled   pci:0000:00:14.0
   HDAS      S4         *disabled  pci:0000:00:1f.3
   I3C0      S4         *disabled
   CNVW      S4         *disabled  pci:0000:00:14.3
   RP01      S4         *disabled
   PXSX      S4         *disabled
   RP02      S4         *disabled
   PXSX      S4         *disabled
   RP03      S4         *disabled
   PXSX      S4         *disabled
   RP04      S4         *disabled
   PXSX      S4         *disabled
   RP05      S4         *disabled
   PXSX      S4         *disabled
   RP06      S4         *disabled
   PXSX      S4         *disabled
   RP07      S4         *disabled
   PXSX      S4         *disabled
   RP08      S4         *disabled
   PXSX      S4         *disabled
   RP09      S4         *enabled   pci:0000:00:06.0
   PXSX      S4         *disabled  pci:0000:01:00.0
   RP10      S4         *disabled
   PXSX      S4         *disabled
   RP11      S4         *disabled
   PXSX      S4         *disabled
   RP12      S4         *disabled
   PXSX      S4         *disabled
   TXHC      S4         *enabled   pci:0000:00:0d.0
   TDM0      S4         *enabled   pci:0000:00:0d.2
   TDM1      S4         *disabled
   TRP0      S4         *disabled
   PXSX      S4         *disabled
   TRP1      S4         *enabled   pci:0000:00:07.0
   PXSX      S4         *disabled
   TRP2      S4         *disabled
   PXSX      S4         *disabled
   TRP3      S4         *disabled
   PXSX      S4         *disabled

As I said, I don't actually understand what I'm doing here, but I'd
really like to learn! It would be really cool if I ended up having to
write and contribute my first driver!

Sorry if I am somehow posting this incorrectly. This is my first time
communicating here, just trying my best.

You already provided a lot of data, good job :).

I think that we do not need another driver in this case, as the xiaomi-wmi driver
is responsible for handling WMI events on Xiaomi devices. I can check what needs
to be done in order to add support for those additional keyboard events, but for
that i need the full output of acpidump.

Thanks,
Armin Wolf

P.S. CC'ing W_Armin@gmx.de, linux@weissschuh.net and fengwk94@gmail.com
since I've got the impression you have some experience with this.