feat: refuse matrix settings a Raspberry Pi 5 can't drive

On a Pi 5 the pinned rgbmatrix library drives the panel through the RP1
chip, and that path supports only row address types 0 and 2, parallel 1-3
and the regular / regular-pi1 / classic / adafruit-hat(-pwm) mappings
(Rp1PioConfigSupported in lib/rp1/rp1_pio_backend.cc). For anything else
CreateFromOptions returns NULL; the Python binding doesn't check, so the
display process crashed on its first call into the matrix and systemd
restarted it into the same crash every 10 seconds.

- src/pi5_matrix_support.py: the rule and Pi 5 detection, matching the
  library's /proc/device-tree/model check
- DisplayManager raises before creating the matrix, so it is a logged init
  failure (reported by /api/v3/hardware/status) and fallback mode
- the config API rejects those settings on a Pi 5 when a request sets
  row_address_type, parallel or hardware_mapping
- the Display form offers only row address types 0 and 2 on a Pi 5, and
  warns when a stored value can't be used
- CLAUDE.md: re-check the rule whenever the submodule is bumped

Review feedback on #586.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Chuck
2026-09-15 18:10:29 -04:00
co-authored by Claude Opus 5
parent 768517a658
commit 2d7a687a02
12 changed files with 348 additions and 12 deletions
+5 -1
View File
@@ -631,6 +631,10 @@ These settings are typically only needed for non-standard panels or custom confi
with an Adafruit Triple LED Matrix Bonnet, 4 left rows jumping; 6–8 gave a
stable image.
- On a Raspberry Pi 5 the rgbmatrix library currently supports only 0 and 2
(and `parallel` 1-3). Anything else would crash the display service, so on
a Pi 5 the web UI offers only 0 and 2, the config API refuses the others,
and if one is set in `config.json` anyway the display logs why and runs in
fallback mode
- Check your panel datasheet if display appears corrupted
- **`multiplexing`** (integer, 0-22, default: 0)
@@ -748,7 +752,7 @@ Controls how long each installed plugin stays visible in seconds before switchin
- Verify `hardware_mapping` matches your HAT/connection type
- Try adjusting `gpio_slowdown`
- Ensure your display doesn't need the E-Addressable line
- If it went blank right after a settings change, check `sudo journalctl -u ledmatrix` for `Failed to initialize RGB Matrix`: the rgbmatrix library refused a value (for example more than 64 `rows`, or `pwm_dither_bits` above 2) and the display fell back to no output. The library's own message nearby names the setting
- If it went blank right after a settings change, check `sudo journalctl -u ledmatrix` for `Failed to initialize RGB Matrix`: the rgbmatrix library refused a value (for example more than 64 `rows`, or `pwm_dither_bits` above 2) and the display fell back to no output. The library's own message nearby names the setting; on a Raspberry Pi 5, LEDMatrix's message names any unsupported `row_address_type`, `parallel` or `hardware_mapping`
- A repeating scramble points at `row_address_type` or `multiplexing`; a panel that stays dark, at `panel_type`
**Rows jump up and down, or the bottom row repeats other rows:**