Linux Systems, Hosting & Infrastructure

kernel From a resume stall to a driver workflow

kpatch is a Go CLI and DKMS driver variant addressing a Linux AMD PMC suspend-to-idle resume delay.

Engineering story View source

Project snapshot · measured 2026-10-26

Key facts

Commits 51Last commit 2026-10-21 Source receipt ↗ Commits · 7 days 1 Source receipt ↗ Tickets closed 11 / 14 Source receipt ↗ Studies 1 Source receipt ↗

12-week commit activity

2026-10-26

Aug 3

Aug 10

Aug 17

Aug 24

Aug 31

Sep 7

Sep 14

Sep 21

Sep 28

Oct 5

Oct 12

Oct 19

View 12-week data table

Week starting	Commits
2026-08-03	0
2026-08-10	0
2026-08-17	0
2026-08-24	0
2026-08-31	0
2026-09-07	0
2026-09-14	0
2026-09-21	42
2026-09-28	0
2026-10-05	7
2026-10-12	0
2026-10-19	1

Key Features

Adds the missing AMD Platform Management Controller (PMC) quirk for this laptop's sleep-resume path.
The kpatch CLI fetches and builds the driver with DKMS, then signs it for Secure Boot.
Switch between patched and stock drivers, check which is active, and inspect wake timing.
An optional debug build reports which hardware quirk is active.

Verified Engineering Milestones

Root cause and driver fix selected (#002, #005, c5327ec)
DKMS driver build and resume delay verified (#006, #007, d3785df, 5e641a0)
Driver management and wake-time diagnostics CLI (#009, ebbdc43)

Stack

Go 1.26.0, Cobra, C Linux kernel driver (AMD Platform Management Controller), DKMS, Secure Boot signing, YAML configuration

Why kernel

A missing AMD PMC quirk caused a roughly ten-second resume delay in the investigated system. An out-of-tree driver variant makes the workaround maintainable while the CLI exposes build, signing, switching, and runtime status.

What it does

Driver lifecycle

Fetch driver sources, build and install through DKMS, manage Secure Boot signing, and switch between patched and stock drivers.

Runtime visibility

Status distinguishes the preferred installed module from runtime state. An optional debug variant exposes the selected quirk through read-only sysfs.

Measured resume timing

A resume timing analyzer supports investigation. The study records three resume-device measurements between 0.473 and 0.475 seconds on the target system.

The workflow

Upstream AMD PMC source
Canary + quirk patch
DKMS build / signing
Variant switch + runtime check

Recent milestones

2026-09-21 — An unmodified DKMS canary build preceded the quirk patch in issues 006–007. d3785df
2026-09-21 — DKMS lifecycle and CLI features were added through issues 008–009. 679d95a
2026-09-21 — The optional debug variant and runtime quirk reporting were completed in issue 011. a97852a

Historical milestones from the review through October 4, 2026.

How the work was verified

The canary reduced uncertainty before patching. Integration fixes made the distinction between the DKMS package amd-pmc-kpatch and the kernel module amd_pmc explicit, corrected DKMS object discovery, and checked stock-module availability before unloading the patched driver.

The October 4 review records 42 commits on September 21 and 21 Go test functions across six files. That concentrated work spans C driver integration, DKMS, Secure Boot, the Go CLI, documentation, and live validation.

Read the October 4 story and its facts table.

Current scope and limits

This is a targeted Linux/AMD PMC workaround. Evidence centers on one target system and three recorded resume cycles; it does not establish compatibility for other hardware or kernels. Go package checks and hardware validation are separate.

Build the CLI

Build and installation targets are maintained in the repository Makefile.

Driver operations additionally depend on DKMS, matching kernel headers, and the signing setup described in the source operating notes.

Project details

Stack

Go 1.26.0, Cobra, C Linux kernel driver (AMD Platform Management Controller), DKMS, Secure Boot signing, YAML configuration

Milestones

Root cause and driver fix selected (#002, #005, c5327ec) · DKMS driver build and resume delay verified (#006, #007, d3785df, 5e641a0) · Driver management and wake-time diagnostics CLI (#009, ebbdc43)

Source

https://codeberg.org/ubunatic/amd-pmc-kpatch ↗

Architecture

Layer composition

Terminal: CLI
Desktop: Linux kernel, DKMS, Secure Boot
Inference / AI: —
Containers / VM: —
Web: —

Engineering story

kernel: the story behind the project

This repository tackles a laptop problem: waking from suspend-to-idle could pause for about ten seconds. The investigation traced the delay to an AMD Platform Management Controller (PMC) quirk missing from the kernel’s DMI table for one mac…

Read the engineering story

Measurement source · 2026-10-26

Verification receipts

Commits: 51 · Last commit 2026-10-21
git -C <repo> rev-list --count HEAD; git -C <repo> rev-list --count --since=<ISO-week-Monday> --until=<ISO-week-Sunday> HEAD; git -C <repo> rev-list --count --since=<measured-date-6-days>T00:00:00 --until=<measured-date>T23:59:59 HEAD; git -C <repo> log -1 --format=%cs HEAD; ls <repo>/issues | grep '^[0-9].*\.md$'; grep -l -E '^\*\*Status\*\*: *(Closed|Done|Resolved|Fixed|Complete)' <repo>/issues/*.md | wc -l; ls <repo>/docs/studies/*.md
repositories behind spec project ids in ~/projects; private-repo filter is a safety net and matches no spec project today; missing repos reported separately; seven calendar days ending on measured date in the measuring host's local timezone; commit counts include all authors and merge commits reachable from HEAD · measured 2026-10-26
Commits · 7 days: 1
git -C <repo> rev-list --count HEAD; git -C <repo> rev-list --count --since=<ISO-week-Monday> --until=<ISO-week-Sunday> HEAD; git -C <repo> rev-list --count --since=<measured-date-6-days>T00:00:00 --until=<measured-date>T23:59:59 HEAD; git -C <repo> log -1 --format=%cs HEAD; ls <repo>/issues | grep '^[0-9].*\.md$'; grep -l -E '^\*\*Status\*\*: *(Closed|Done|Resolved|Fixed|Complete)' <repo>/issues/*.md | wc -l; ls <repo>/docs/studies/*.md
repositories behind spec project ids in ~/projects; private-repo filter is a safety net and matches no spec project today; missing repos reported separately; seven calendar days ending on measured date in the measuring host's local timezone; commit counts include all authors and merge commits reachable from HEAD · measured 2026-10-26
Tickets closed: 11 / 14
git -C <repo> rev-list --count HEAD; git -C <repo> rev-list --count --since=<ISO-week-Monday> --until=<ISO-week-Sunday> HEAD; git -C <repo> rev-list --count --since=<measured-date-6-days>T00:00:00 --until=<measured-date>T23:59:59 HEAD; git -C <repo> log -1 --format=%cs HEAD; ls <repo>/issues | grep '^[0-9].*\.md$'; grep -l -E '^\*\*Status\*\*: *(Closed|Done|Resolved|Fixed|Complete)' <repo>/issues/*.md | wc -l; ls <repo>/docs/studies/*.md
repositories behind spec project ids in ~/projects; private-repo filter is a safety net and matches no spec project today; missing repos reported separately; seven calendar days ending on measured date in the measuring host's local timezone; commit counts include all authors and merge commits reachable from HEAD · measured 2026-10-26
Studies: 1
git -C <repo> rev-list --count HEAD; git -C <repo> rev-list --count --since=<ISO-week-Monday> --until=<ISO-week-Sunday> HEAD; git -C <repo> rev-list --count --since=<measured-date-6-days>T00:00:00 --until=<measured-date>T23:59:59 HEAD; git -C <repo> log -1 --format=%cs HEAD; ls <repo>/issues | grep '^[0-9].*\.md$'; grep -l -E '^\*\*Status\*\*: *(Closed|Done|Resolved|Fixed|Complete)' <repo>/issues/*.md | wc -l; ls <repo>/docs/studies/*.md
repositories behind spec project ids in ~/projects; private-repo filter is a safety net and matches no spec project today; missing repos reported separately; seven calendar days ending on measured date in the measuring host's local timezone; commit counts include all authors and merge commits reachable from HEAD · measured 2026-10-26
12-week commit activity
git rev-list --count --since=<Monday> --until=<Sunday> HEAD
12 latest complete ISO weeks; weekly values are from spec/metrics.yaml.