Public bug reported:
Description:
On Ubuntu 26.04, the built-in keyboard of the Lenovo IdeaPad Slim 3 15ARP10
(Ryzen 7 7735HS) becomes completely inactive/unresponsive after waking up from
modern standby (s2idle). The keyboard only works again after a full system
reboot.
Steps to reproduce:
1. Boot into Ubuntu 26.04.
2. Put the laptop to suspend (s2idle).
3. Wake the laptop up. The built-in keyboard is completely dead.
Current Workaround found:
The issue can be temporarily resolved by forcing the AMD Power Management
Controller to enable the Smart Trace Buffer (STB) via modprobe.
Creating '/etc/modprobe.d/amd_pmc.conf' with the following line fixes the
keyboard lock:
options amd_pmc enable_stb=1
This configuration was extracted and dissected from Lenovo's custom
"Lux" OS (which uses a modified 6.12+ kernel), where the keyboard works
out-of-the-box.
CRITICAL SIDE EFFECTS (Why a proper kernel patch is needed):
While 'enable_stb=1' keeps the keyboard working after resume, it introduces a
severe power management regression: it prevents the laptop from reaching its
deepest hardware sleep state (Deep Sleep / S3 is already blocked by Lenovo's
BIOS, and s2idle cannot achieve optimal low-power state with STB enabled). This
causes abnormal battery drain during suspend.
We need a proper kernel quirk/patch for the 'amd_pmc' module on this
specific hardware family so the keyboard interrupt mapping isn't lost
during s2idle without needing to force STB on.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-15-generic 7.0.0-15.15
ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0
Uname: Linux 7.0.0-15-generic x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: kaikialmeida_ 13941 F.... wireplumber
/dev/snd/controlC0: kaikialmeida_ 13941 F.... wireplumber
/dev/snd/seq: kaikialmeida_ 13939 F.... pipewire
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Thu May 28 16:59:53 2026
InstallationDate: Installed on 2026-04-19 (39 days ago)
InstallationMedia: Ubuntu 24.04.4 LTS "Noble Numbat" - Release amd64 (20260210)
MachineType: LENOVO 83MM
ProcEnviron:
LANG=pt_BR.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-15-generic
root=UUID=b607854b-1cb1-4013-b478-3b2fadc2bd0d ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-04-25 (33 days ago)
dmi.bios.date: 01/15/2026
dmi.bios.release: 1.29
dmi.bios.vendor: LENOVO
dmi.bios.version: QBCN29WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: NO DPK
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: IdeaPad Slim 3 15ARP10
dmi.ec.firmware.release: 1.26
dmi.modalias:
dmi:bvnLENOVO:bvrQBCN29WW:bd01/15/2026:br1.29:efr1.26:svnLENOVO:pn83MM:pvrIdeaPadSlim315ARP10:rvnLENOVO:rnLNVNB161216:rvrNODPK:cvnLENOVO:ct10:cvrIdeaPadSlim315ARP10:skuLENOVO_MT_83MM_BU_idea_FM_IdeaPadSlim315ARP10:pfaIdeaPadSlim315ARP10:
dmi.product.family: IdeaPad Slim 3 15ARP10
dmi.product.name: 83MM
dmi.product.sku: LENOVO_MT_83MM_BU_idea_FM_IdeaPad Slim 3 15ARP10
dmi.product.version: IdeaPad Slim 3 15ARP10
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2154508
Title:
Lenovo Slim 3 15ARP10 keyboard unresponsive after resume from s2idle
(AMD PMC STB issue)
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