Playbook: wifi, bluetooth and modem
scope: generic · severity: technique · confidence: proven · subsystem: radio
Goal: the radios come up, stay up, and survive suspend.
Done when: a wifi association survives a rekey and a suspend/resume, and restarts are zero over a long soak — not merely “it connected once”.
Order
Section: Order- Firmware first, and check ownership not presence. A firmware file that exists is not the same as a firmware file the package recorded — [[apk-info-W-wants-the-path-the-package-recorded]].
- Bring-up before stability. Association is the easy half. Rekey, roaming and suspend/resume are where the real bugs are.
- Soak. Radio bugs are statistical. A single successful connection tells you almost nothing.
The traps
Section: The traps- installing-firmware-can-flash-the-boot-partition — installing the firmware
package can
dda boot image, mid-session - dmesg-can-be-empty-about-boot — a WARN storm from a radio driver is
itself the thing that destroys your evidence about everything else. If a
radio driver is logging repeatedly, fix that before you trust any
dmesgon this device.