dotfiles/zz-blankpad/niri/.config/niri/cfg/desk-1-home.kdl

@@ -7,8 +7,12 @@
 // requires: Lenovo Group Limited 0x40A9 Unknown
 // optional: HDMI-A-1 (PM1601, dock-dependent)
 
+// This panel's EDID tops out at 3440x1440@180 (read live from niri: no 240 Hz mode
+// exists). Ask for a mode the panel does not offer and niri does not fail — it logs
+// "could not be found, falling back to preferred" and drops to 60 Hz on every
+// reconnect. Keep 180 here unless a re-read EDID says otherwise.
 output "Sceptre Tech Inc Sceptre M34 Unknown" {
-    mode "3440x1440@239.999"
+    mode "3440x1440@180.000"
     scale 1
     transform "normal"
     position x=1581 y=-600
@@ -47,7 +51,7 @@ output "eDP-1" {
     position x=-339 y=-240
 }
 output "DP-1" {
-    mode "3440x1440@120.000"
+    mode "3440x1440@180.000"
 
     scale 1.0
 

omp-docs/log.md

@@ -6,7 +6,7 @@ tags:
   - okf
   - maintenance
   - changelog
-timestamp: 2026-10-19
+timestamp: 2026-10-21
 ---
 
 # Bundle Change Log
@@ -20,6 +20,33 @@ This page is the bundle's **only** work log: one file, at the root. Never start
 second one in a subdirectory or under another name — `scripts/kb-lint.sh` reports any
 `log.md` that is not this one.
 
+## 2026-10-21 — a documented mode the panel never had
+
+The home ultrawide had been running at 60 Hz for weeks while `desk-1-home.kdl`
+asked for `3440x1440@239.999`. The page that owns that file documented the same
+phantom mode, so every reader — including tonight's inspection — trusted it.
+`niri msg outputs` says the Sceptre M34's EDID tops out at 180 Hz; there is no
+240 Hz mode to ask for.
+
+Laws, now on [tools/niri/displays](tools/niri/displays.md):
+
+- **An impossible mode does not fail, it falls back.** niri logs
+  `configured mode … could not be found, falling back to preferred` and drives
+  the EDID preferred mode — 60 Hz here. A config typo therefore looks like a
+  dying monitor, and every connector drop re-enacts it.
+- **Three layers, three signatures:** config fallback, DP link drops, and
+  amdgpu `DMCUB` errors with `EINVAL` page flips after s2idle. Only the first
+  yields to a file edit; only the last yields to a reboot. Triage table and
+  probes are on the page.
+- **A number in a page is a claim, not a measurement.** Modes, refresh rates and
+  tool availability were wrong on four pages at once — `wlr-randr` was listed as
+  installed while `pacman -Qs wlr` matches nothing. Read the hardware before
+  writing a mode into a runbook, and destroy the stale copies.
+
+Fix: `desk-1-home.kdl` 239.999 → 180.000 on the identity block and both legacy
+connector blocks, applied live with `niri msg output <panel> mode <mode>` — the
+temporary per-output path, so no config reload and no logged-out session.
+
 ## 2026-10-20 — one work log per bundle
 
 The bundle had two: this page and `core/log.md`, created "for tracking core

omp-docs/tools/applications.md

@@ -33,7 +33,6 @@ Applications that ship with or are configured on CachyOS with Niri on the workst
 | **Noctalia Shell** | 4.7.7 | Desktop shell (launcher, wallpaper, session menu) |
 | **Shelly Notifications** | — | Notification daemon |
 | **pavucontrol** | — | Audio mixer |
-| **wlr-randr** | — | Display management |
 
 ## Screenshot and Recording
 

omp-docs/tools/cachyos.md

@@ -95,7 +95,6 @@ CachyOS with Niri ships with a curated set of applications:
 - **wf-recorder** — Screen recording
 - **hyprpicker** — Color picker
 - **wl-clipboard** — Clipboard management
-- **wlr-randr** — Display management
 - **NetworkManager** — Network management
 - **BlueZ** — Bluetooth
 - **pavucontrol** — Audio mixer

omp-docs/tools/niri/displays.md

@@ -1,14 +1,14 @@
 ---
 type: reference
 title: Display Configuration
-description: Niri output configuration on blankpad — EDID-identity-keyed desk profiles, hotplug auto-switching, portrait transforms, position pinning, and GPU notes (AMD Cezanne now; Intel Arc render-node pin is dankware-legacy).
+description: Niri output configuration on blankpad — EDID-identity-keyed desk profiles, hotplug auto-switching, portrait transforms, position pinning, the phantom-mode fallback trap, and GPU notes (AMD Cezanne now; Intel Arc render-node pin is dankware-legacy).
 tags:
   - niri
   - display
   - monitors
   - rotation
   - desk-profiles
-verified: 2026-10-09
+verified: 2026-10-21
 ---
 
 # Display Configuration
@@ -24,7 +24,11 @@ active profile (`desk-1-home.kdl`, `desk-2-portable.kdl`, …).
 `config.kdl` includes it with `include optional=true` so a missing link is a
 warning, not a parse failure.
 **Probe:** `niri msg outputs` is authoritative (connector, full EDID long
-name, modes, transform, scale, position, VRR). `wlr-randr` remains available.
+name, modes, transform, scale, position, VRR). Per-output changes go live with
+`niri msg output <name> <mode|scale|transform|position|off|on>` and are
+temporary — never written to the config file. `wlr-randr` is **not installed**
+on blankpad (`pacman -Qs wlr` matches nothing, verified 2026-10-21); pages that
+list it as an installed tool are stale.
 
 ---
 
@@ -33,7 +37,7 @@ name, modes, transform, scale, position, VRR). `wlr-randr` remains available.
 ```
 ┌──────────────┬──────────────────────────────┬──────────┐
 │  PM1601      │   Sceptre M34 ultrawide      │  eDP-1   │
-│  portrait    │   3440x1440 @ 239.999        │ 1920x1080│
+│  portrait    │   3440x1440 @ 180.000        │ 1920x1080│
 │  1200x1920   │   landscape, scale 1         │ scale 1  │
 │  rot 90      │   position 1581,-600         │ 5021,-240│
 └──────────────┴──────────────────────────────┴──────────┘
@@ -42,7 +46,7 @@ name, modes, transform, scale, position, VRR). `wlr-randr` remains available.
 
 | Panel | EDID long name | Keyed by | Notes |
 |-------|----------------|----------|-------|
-| Sceptre M34 ultrawide | `Sceptre Tech Inc Sceptre M34 Unknown` | identity | `mode "3440x1440@239.999"`, `focus-at-startup` |
+| Sceptre M34 ultrawide | `Sceptre Tech Inc Sceptre M34 Unknown` | identity | `mode "3440x1440@180.000"` — the EDID maximum; no 240 Hz mode exists — `focus-at-startup` |
 | PM1601 portrait | *not captured* | connector `HDMI-A-1` | dock-dependent; run `desk.sh capture` when plugged in, then re-key |
 | eDP-1 laptop panel | `Lenovo Group Limited 0x40A9 Unknown` | identity | scale **1.0** (deliberate; Ghostty grid at 1.25 rejected 2026-10-09), second `focus-at-startup` |
 
@@ -84,7 +88,7 @@ graph LR
 ```kdl
 // desk-1-home.kdl — one block per panel, keyed by identity
 output "Sceptre Tech Inc Sceptre M34 Unknown" {
-    mode "3440x1440@239.999"
+    mode "3440x1440@180.000"
     scale 1
     transform "normal"
     position x=1581 y=-600
@@ -98,6 +102,10 @@ Four rules learned the hard way:
    name *and* long name) fight over properties — transform reverts are the
    classic symptom. Desk profiles are self-contained: a panel's identity,
    mode, transform, **and** position live in exactly one block per file.
+   `desk-1-home.kdl` still carries legacy connector-keyed `DP-1` / `DP-2`
+   blocks next to the identity block. Their modes were aligned to 180 Hz on
+   2026-10-21 so a connector-named reconnect cannot drop the panel to 120, but
+   they belong folded into the identity block.
 2. **Key by EDID identity, not connector.** Connector names swap between
    docks; the EDID long name travels with the panel. Serials on these panels
    read `Unknown`, so the full long name (manufacturer model serial) is the
@@ -105,8 +113,47 @@ Four rules learned the hard way:
 3. **Positions are absolute, not relational.** A disconnected panel leaves
    a hole; that is exactly why positions belong to the *desk profile*, not a
    global file.
-4. **Modes must match what the panel reports** (`niri msg outputs` →
+4. **Ask only for modes the panel reports** (`niri msg outputs` → `Mode:` list).
-   `Mode: current …`). A mode the panel cannot drive leaves the output dark.
+   A mode the panel never offered does **not** leave the output dark: niri logs
+   `configured mode … could not be found, falling back to preferred` and quietly
+   drives the panel at its EDID *preferred* mode — **60 Hz** on the M34. Nothing
+   looks broken except the refresh rate, and every reconnect repeats the
+   fallback. Check Hz, not just resolution, after any "monitor is acting up".
+
+## "The monitors are broken" — three layers, three signatures
+
+A display complaint belongs to one of three layers. Sort it before editing
+config, because the config is usually innocent — and when it is guilty, the
+guilt may have been copied from this page.
+
+| Layer | Log signature | Reality | Move |
+|-------|---------------|---------|------|
+| Config | `configured mode … could not be found, falling back to preferred` | a mode/scale the panel never offered | re-read the mode list with `niri msg outputs` and correct the file; do **not** trust a documented mode |
+| Link | `disconnecting connector: "DP-1"` followed seconds later by `new connector: DP-1`, recurring | the DP link itself dropping — cable, dock, the monitor's DP-version/DSC setting, or panel power saving | every drop re-runs mode selection, so a config error is re-enacted in public; swap the cable before blaming the compositor |
+| Driver | `Page flip commit failed … (Invalid argument)` plus kernel `*ERROR* … DMCUB error` | amdgpu's display engine wedged, typically after an s2idle resume | survives until a reboot; niri keeps running while the panel keeps dropping. No config edit clears it |
+
+Probes, in this order:
+
+```bash
+niri msg outputs                    # connector, EDID long name, real mode list, current mode
+journalctl --user -b | grep -E 'disconnecting connector|Page flip commit failed|falling back to preferred'
+journalctl -k -b  | grep -iE 'amdgpu.*(ERROR|DMCUB)|PM: suspend exit'
+```
+
+Correlate the drop timestamps against `PM: suspend exit` first. A resume a
+minute before the first drop is the cause; the config file is not.
+
+To fix a refresh rate without disturbing the session, use the temporary
+per-output path — it touches one output, applies no config, reloads nothing:
+
+```bash
+niri msg output "Sceptre Tech Inc Sceptre M34 Unknown" mode "3440x1440@180.000"
+```
+
+It is temporary by design, so correct the profile too and let the next
+reconnect or `load-config-file` make it permanent. With the display engine
+already throwing `EINVAL`, prefer the per-output path over a full config
+reload; on a healthy machine either is fine.
 
 ## GPU assignment
 
@@ -132,4 +179,4 @@ symlink matrix]]).
 - [Niri](/tools/niri/index.md) — compositor overview and config layout
 - [[tips|tips]] — reload path, `niri msg layers/casts`, includes
 - [[noctalia-shell|noctalia-shell]] — notification shown on desk switch
-- [[cachyos|cachyos]] — operating system, including `wlr-randr`
+- [[cachyos|cachyos]] — operating system