From 56c934e97e22bbcb01186e7ef12a857cc74f403b Mon Sep 17 00:00:00 2001
From: Julien Calixte <julien.calixte@theodo.com>
Date: Thu, 14 May 2026 12:45:12 +0200
Subject: [PATCH] docs(adr): correct ADR-006 stack budget to 76 KB
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Prior text said "~40 KB of stack space"; the v0.1 technical design's
task table sums to 76 KB (usb 8 + wifi 8 + ui 16 + render 12 + git 32).
Also widens the std::thread stack-cost note from a flat 8 KB to 8–32 KB
to match the per-task budget. No design change — 76 KB still fits
comfortably in the ESP32-S3's 512 KB internal SRAM.
---
 docs/adr.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/docs/adr.md b/docs/adr.md
index 4be86e8..ef4ff05 100644
--- a/docs/adr.md
+++ b/docs/adr.md
@@ -197,7 +197,7 @@ the scale where async wins. The number of "tasks" is bounded and small (≤ 8).
 
 | Option | Pros | Cons |
 |---|---|---|
-| **`std::thread` + channels** | Boring, debuggable, stack traces work, no executor to tune; ESP-IDF FreeRTOS underneath is well-understood. | Each thread costs ~8 KB stack; not zero-cost like async. |
+| **`std::thread` + channels** | Boring, debuggable, stack traces work, no executor to tune; ESP-IDF FreeRTOS underneath is well-understood. | Each thread costs 8–32 KB stack depending on workload; not zero-cost like async. |
 | **`embassy` async** | Trendy, ergonomic, low memory per task. | `esp-idf-rs` and `embassy` don't mix cleanly; adopting embassy means dropping `std` and rewriting against `esp-hal` (ADR-001 reversed). |
 | **`tokio` on `esp-idf-rs`** | Familiar async. | Heavy executor, oversized for ≤ 8 tasks, mbedtls/`gitoxide` integration would need a lot of glue. |
 | **Single-threaded event loop** | Smallest memory. | Long-running ops (git push, full refresh) block input. |
@@ -208,7 +208,9 @@ the scale where async wins. The number of "tasks" is bounded and small (≤ 8).
 runtime to tune, no colour-of-functions problem.
 
 ### Consequences
-- ~40 KB of stack space for task stacks. Easily affordable.
+- ~76 KB of stack space across the five task stacks (8 + 8 + 16 + 12 + 32
+  KB — see v0.1 technical design for the breakdown). Comfortable in the
+  ESP32-S3's 512 KB internal SRAM.
 - Refresh / git / Wi-Fi each get their own thread, so a slow push doesn't
   freeze typing.
 - If task count balloons past ~10 (unlikely), revisit.