[update] action to install alsa on linux builds and update documentation to specify the requirement for it.

Author: vmarcella

.github/workflows/compile_lambda_rs.yml

@@ -48,6 +48,7 @@ jobs:
             pkg-config libx11-dev libxcb1-dev libxcb-render0-dev \
             libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev \
             libwayland-dev libudev-dev \
+            libasound2-dev \
             libvulkan-dev libvulkan1 mesa-vulkan-drivers vulkan-tools
 
       - name: Configure Vulkan (Ubuntu)

docs/features.md

@@ -3,13 +3,13 @@ title: "Cargo Features Overview"
 document_id: "features-2025-11-17"
 status: "living"
 created: "2025-11-17T23:59:00Z"
-last_updated: "2026-01-30T22:48:05Z"
-version: "0.1.9"
+last_updated: "2026-01-30T23:40:49Z"
+version: "0.1.10"
 engine_workspace_version: "2023.1.30"
 wgpu_version: "26.0.1"
 shader_backend_default: "naga"
 winit_version: "0.29.10"
-repo_commit: "e179f7de3b43f9cd822b4f7ab520c095dc3c6911"
+repo_commit: "df62c624ca869e0493a3a92297d1cebe94251e69"
 owners: ["lambda-sh"]
 reviewers: ["engine", "rendering"]
 tags: ["guide", "features", "validation", "cargo", "audio"]
@@ -33,6 +33,9 @@ relationships, and expected behavior in debug and release builds.
 - Release builds enable only cheap safety checks by default; validation logs and per-draw checks MUST be enabled explicitly via features.
 - Audio support in `lambda-rs` is enabled by default and incurs runtime cost
   only when an audio device is initialized and kept alive.
+  - Linux builds that include the default audio backend MUST provide ALSA
+    development headers and `pkg-config` (for example, `libasound2-dev` on
+    Debian/Ubuntu).
 
 ## lambda-rs
 
@@ -132,6 +135,8 @@ Audio
   backend module `lambda_platform::cpal` backed by `cpal =0.17.1`.
 
 ## Changelog
+- 0.1.10 (2026-01-30): Document Linux system dependencies required by the
+  default audio backend.
 - 0.1.9 (2026-01-30): Clarify workspace default audio behavior after enabling
   `lambda-rs` audio features by default.
 - 0.1.8 (2026-01-30): Enable `lambda-rs` audio features by default and update

docs/specs/audio-devices.md

@@ -3,13 +3,13 @@ title: "Audio Device Abstraction"
 document_id: "audio-device-abstraction-2026-01-28"
 status: "draft"
 created: "2026-01-28T22:59:00Z"
-last_updated: "2026-01-30T23:21:06Z"
-version: "0.1.12"
+last_updated: "2026-01-30T23:40:49Z"
+version: "0.1.13"
 engine_workspace_version: "2023.1.30"
 wgpu_version: "26.0.1"
 shader_backend_default: "naga"
 winit_version: "0.29.10"
-repo_commit: "7e7851da903fbc7b4aa35acd511999df659af237"
+repo_commit: "df62c624ca869e0493a3a92297d1cebe94251e69"
 owners: ["lambda-sh"]
 reviewers: ["engine", "rendering"]
 tags: ["spec", "audio", "lambda-rs", "platform", "cpal"]
@@ -555,6 +555,9 @@ Feature gating requirements
   - It MUST NOT perform I/O.
 - User-provided output callbacks MUST follow the same real-time safety rules as
   the stream callback.
+- Linux builds with `audio-output-device` enabled MUST provide ALSA development
+  headers and `pkg-config` so the `alsa-sys` dependency can link successfully
+  (for example, `libasound2-dev` on Debian/Ubuntu).
 
 ## Performance Considerations
 
@@ -653,6 +656,8 @@ Manual checks
 
 ## Changelog
 
+- 2026-01-30 (v0.1.13) — Document Linux system dependencies required by the
+  default audio backend.
 - 2026-01-30 (v0.1.12) — Populate the requirements checklist with file
   references matching the implemented surface.
 - 2026-01-30 (v0.1.11) — Align examples with the `lambda` crate name, document