Control: reassign -1 src:linux 6.18.15-1 Control: tags -1 + moreinfo On Wed, Mar 18, 2026 at 11:01:08AM +0000, Andrea V wrote: > Source: linux-signed-amd64 > Severity: important > Tags: upstream > > Subject: linux-image-6.18.15+deb13-amd64: suspend via s2idle fails to reach > S0i3 on ThinkPad T14s Gen 4 AMD, while 6.12.74 works > > Package: linux-image-6.18.15+deb13-amd64 > Version: 6.18.15-1~bpo13+1 > Severity: important > Tags: upstream > > Dear Debian Kernel Team, > > I am reporting what appears to be a suspend regression in the Debian backports > kernel on a Lenovo ThinkPad T14s Gen 4 AMD (type 21F8CTO1WW). > > Summary > ------- > On linux-image-6.18.15+deb13-amd64 (6.18.15-1~bpo13+1), suspend enters s2idle > but fails to reach S0i3 / deep low-power idle. The laptop "suspends", but the > fan keeps running and power draw remains high. > > On the same machine, the Debian security kernel > linux-image-6.12.74+deb13+1-amd64 (6.12.74-2) works correctly: s2idle reaches > S0i3 successfully and the machine suspends properly. > > System > ------ > - Model: Lenovo ThinkPad T14s Gen 4 AMD (21F8CTO1WW) > - CPU: AMD Ryzen 7 PRO 7840U > - BIOS before testing: 1.25 > - BIOS updated during debugging via fwupd to: 1.29 > - mem_sleep: [s2idle] > - The platform exposes S0/S4/S5 only; no "deep"/S3 is available > > Regression comparison > --------------------- > Working kernel: > - linux-image-6.12.74+deb13+1-amd64 > - version 6.12.74-2 > > Failing kernel: > - linux-image-6.18.15+deb13-amd64 > - version 6.18.15-1~bpo13+1 > > Both kernels were tested on the same machine and firmware. > > Behavior on failing kernel (6.18.15-1~bpo13+1) > ----------------------------------------------- > Relevant journal excerpts from the failing boot: > > Linux version 6.18.15+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian > 6.18.15-1~bpo13+1 > ACPI: PM: (supports S0 S4 S5) > Low-power S0 idle used by default for system suspend > systemd-sleep: Performing sleep operation 'suspend'... > PM: suspend entry (s2idle) > amd_pmc AMDI0009:00: Last suspend didn't reach deepest state > systemd-sleep: System returned from sleep operation 'suspend' > PM: suspend exit > > During testing on 6.18, AMD PMC debugfs showed: > - S0ix Residency Time: 0 > - Last S0i3 Status: Unknown/Fail > > Observed user-visible effect: > - laptop appears suspended > - but fan keeps spinning > - opening the lid resumes the machine > > Behavior on working kernel (6.12.74-2) > -------------------------------------- > On 6.12.74+deb13+1-amd64, the same machine suspends correctly. > > AMD PMC debugfs on the working 6.12 kernel reports: > - Last S0i3 Status: Success > - Time in S0i3: 9852905 us > - Residency Time: 9852905 > > This strongly suggests a regression between the two Debian kernel versions. > > What was already tested > ----------------------- > - BIOS updated from 1.25 to 1.29: no fix for 6.18 behavior > - acpi.ec_no_wakeup=1: no fix for 6.18 behavior > - Suspend tested with and without USB-C dock attached > - Suspend tested with dock-side USB/Thunderbolt wake settings adjusted > - The separate lid-close/logind issue was fixed independently and is unrelated > > Potentially relevant hardware path > ---------------------------------- > This platform includes AMD Pink Sardine USB4/Thunderbolt controllers: > - 0000:c5:00.5 > - 0000:c5:00.6 > > While debugging 6.18, amd_pmc debug output suggested USB4 activity remained > significant when suspend failed, but the regression remains reproducible even > after disconnecting the dock. > > Installed package versions > -------------------------- > - linux-image-6.18.15+deb13-amd64: 6.18.15-1~bpo13+1 > - linux-image-6.12.74+deb13+1-amd64: 6.12.74-2 > - amd64-microcode: 3.20250311.1 > - firmware-linux / firmware-linux-nonfree: 20260110-1~bpo13+1 > > If needed, I can provide additional logs, but the key point is: > - 6.18 backports fails to reach S0i3 on suspend > - 6.12 on the same machine succeeds
As we won't provide more updates to kernels with the 6.18 series, and moved to 6.19 (with a bpo upload pending as well yet), can you confirm if the issue persists with 6.19.8-1 from unstable? Regards, Salvatore
