diff --git a/TODO.md b/TODO.md new file mode 100644 index 0000000..300e719 --- /dev/null +++ b/TODO.md @@ -0,0 +1,134 @@ +# TODO — remaining items from the 2026-08-03 code review + +Context for whoever (human or AI agent) picks this up. A full review of this +firmware was done on 2026-08-03. The outright bugs it found were fixed in +commit `dd2d428` ("Fix WiFi reconnect bugs, negative-temp rounding, and stale +docs"). This file holds the items that were deliberately **not** done in that +commit — design-level changes and enhancements — plus the facts the review +already established so you don't re-derive or re-ask them. + +Read `README.md` first. It is accurate as of `dd2d428` and documents the +hardware constraints that make this board unusual (PSRAM bandwidth, the +STC8H1K28 board controller, init-order requirements). Do not violate the +init order in `main.c`: WiFi/NVS before `display_init()`, `backlight_init()` +before `touch_init()`. + +## Already verified — do not re-investigate + +- The build compiles clean on ESP-IDF v5.3 (`. ~/esp/esp-idf/export.sh && + idf.py build`). Binary is ~1.1 MB, 74% of the 4 MB factory partition free. +- `main/app_config.h` exists locally (gitignored, copied from the example + with empty credentials, done only to make the build compile). Real WiFi + + Ambient Weather credentials still need to be filled in before flashing. +- `resp_buf` bounds/NUL-termination in `ambient_weather.c` is correct — the + guard leaves room for the terminator. Not a bug. +- GT911 read-then-clear-status ordering in `touch_gt911.c` is correct. +- Backlight duty inversion in `backlight.c` maps correctly at both endpoints + (255→0x00 full, 0→0xF5 off). +- The `°` glyph exists in LVGL's built-in Montserrat fonts; the `·` separator + that does NOT exist in them only appears in log strings, never on screen. +- The LVGL recursive-mutex locking discipline is consistent across all UI + entry points. +- WiFi reconnect, `wifi_is_connected()` staleness, boot-timeout handling, and + negative-temperature rounding were all fixed in `dd2d428`. Don't redo them. + +## Tasks, in priority order + +### 1. Stop freezing the UI during weather fetches + +**Problem:** `weather_update_task` in `main.c` wraps the whole HTTP fetch in +`lvgl_port_pause()`/`resume()`. Pause stops `lv_timer_handler()` entirely, so +rendering AND touch input are dead for the whole fetch — worst case +`WEATHER_TIMEOUT_MS` (30 s), every 60 s. Harmless while the screen is +passive; a showstopper once thermostat controls (setpoint buttons) exist, +which is the stated next step in the README. + +**Why the pause exists:** the TLS session, the LVGL redraw, and the flush all +contend with the LCD's own DMA out of PSRAM; overlapping them produces the +left-edge artefacts documented in the README. Do not simply delete the pause +— the artefacts will come back. Options, roughly in order of preference: + +- Keep the HTTP client alive between polls (`keep_alive_enable` in + `esp_http_client_config_t`, don't `cleanup` between calls). The expensive + part is the TLS handshake; a reused session makes each poll a short + request/response, so the paused window shrinks from seconds to ~100s of ms. +- After the first successful fetch, drop the timeout from 30 s to ~10 s (the + 30 s exists only because a *first* handshake on this board is slow). +- Alternatively pause only around LVGL's flush (the actual PSRAM writes) + rather than the whole network transaction — more invasive, only if the + above is insufficient. + +**Verify on hardware**: watch for the left-edge artefacts after weather +fetches (they appear near the moment the status line updates). This cannot be +verified by compiling alone. + +### 2. Indicate stale weather data + +`weather_data_t.last_update` is set in `ambient_weather.c` but never read. +After fetch failures the old temperature stays on screen at full styling +indefinitely. Track the last successful update (the weather task is the +natural owner); after ~2 missed polls, dim the temperature label +(e.g. change its text color) or append the age to the status line. Keep it in +the weather task / `ui_manager` — do not add timekeeping to the API client. + +### 3. Remove the debug touch readout from the production UI + +`touch_label` + `touch_readout_timer_cb` + the 100 ms `lv_timer` in +`ui_manager.c` are bring-up diagnostics baked into the shipped screen. Remove +them or gate behind a compile-time flag (e.g. `#ifdef UI_DEBUG_TOUCH`, +default off). Keep the explanatory comment about LVGL not bubbling events to +parents somewhere — it documents a real trap that cost debugging time. + +### 4. Delete dead code: `main/utils/utils.c` + +`utils_delay_ms`, `utils_get_tick_ms`, `utils_trim` have zero callers; +nothing outside utils.c includes `utils.h`. Delete `main/utils/` and remove +its entries from `main/CMakeLists.txt` (SRCS and INCLUDE_DIRS), and drop the +row from README's Components table and from `project_structure.txt`. +`touch_get_indev()`, `display_get_panel()`, `lvgl_port_is_paused()` are also +currently uncalled but were deliberately KEPT as driver API surface — leave +them. + +### 5. Add OTA partitions while the fleet is size zero + +16 MB flash, but `partitions.csv` has a single 4 MB factory app and a ~12 MB +SPIFFS partition nothing mounts. Re-partitioning fielded devices later means +reflashing over USB, so lay out `otadata` + `ota_0` + `ota_1` now (two 4 MB +slots fit easily; shrink or drop the unused SPIFFS partition). Note +`CONFIG_ESP_WIFI_NVS_ENABLED=n` and the flash-write-while-panel-running +constraint (README "Memory notes"): an OTA *write* happens while the panel is +scanning, which will fault the bounce-buffer ISR. Any future OTA +implementation must pause/stop the panel during the download+write, or +restart into a dedicated updater mode. Adding the partition layout now is +safe; implementing OTA download is a separate, harder task. + +### 6. Small cleanups (batch into one commit) + +- `ambient_weather.c` truncation path: the "Response exceeds N bytes" warning + logs once per remaining chunk and then JSON parse fails anyway. Log once + (set a flag) and consider aborting the transfer. +- Weather task stack is 6144 bytes with the TLS handshake running in-task. + Works (mbedTLS heap goes to PSRAM via `CONFIG_MBEDTLS_EXTERNAL_MEM_ALLOC`) + but tight — log `uxTaskGetStackHighWaterMark(NULL)` once after a successful + fetch and right-size before more features land in that task. +- `backlight_set()` is only ever called once with 255. A night-dim schedule + or touch-to-wake is a natural small feature; note the STC8H1K28 shares the + I2C bus with the GT911, so calls must stay in task context (never ISRs) and + brightness writes contend with touch polls on the same bus. + +## Questions already asked and answered (don't re-ask the user) + +- **"Should the bugs be fixed or just reported?"** — Answered: fix and + commit. That happened in `dd2d428`. The items in this file were explicitly + left for later; the user has seen this list and asked for it to be recorded + here. Proceeding with these tasks does not need re-confirmation, but + hardware-verification steps (task 1) need a human with the board. +- **"Is the bounce buffer supposed to be enabled?"** — Yes. The README + previously contradicted the code; fixed in `dd2d428`. It is enabled and + load-bearing. +- **"Is the board N4R8 or N16R8?"** — N16R8 (16 MB flash / 8 MB octal + PSRAM). The old sdkconfig header comment saying N4R8 was stale; fixed. +- **"Why is WiFi brought up before the display?"** — Deliberate and + required; see README "Gotchas". Never reorder. +- **"Why is rendering paused during fetches?"** — Deliberate mitigation for + PSRAM bus contention (see task 1). Improve it, don't just remove it.