遇到功耗异常，第一件事就是打开 kernel log。这里面藏着大量电源管理信息。说白了，系统在睡觉还是醒着，谁把它叫醒了，都能从日志里找到线索。
解读 kernel log 中的电源管理信息
MTK 平台的 kernel log 里，电源管理相关的信息主要分布在几个关键位置。我一般用 dmesg 命令来抓取，然后配合 grep 过滤。
先看一个典型的待机日志片段：
[ 12.345678] PM: suspend entry 2024-01-15 10:30:00.123456789 UTC [ 12.345679] PM: Syncing filesystems ... done. [ 12.345680] PM: Freezing user space processes ... [ 12.456789] PM: Freezing user space processes completed [ 12.456790] PM: Freezing remaining freezable tasks ... [ 12.567890] PM: Freezing remaining freezable tasks completed [ 12.567891] Suspending console(s) (use no_console_suspend to debug) [ 12.567892] mtk-suspend: enter sleep state [ 12.567893] mtk-suspend: wakeup source timer (0) [
