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| -rw-r--r-- | 2026/08/29/给一台Linux笔记本做服务器化改造：休眠、充电上限与EC寄存器考古/index.html | 23 |
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diff --git a/2026/08/29/给一台Linux笔记本做服务器化改造：休眠、充电上限与EC寄存器考古/index.html b/2026/08/29/给一台Linux笔记本做服务器化改造：休眠、充电上限与EC寄存器考古/index.html index 2420a461..f93eb930 100644 --- a/2026/08/29/给一台Linux笔记本做服务器化改造：休眠、充电上限与EC寄存器考古/index.html +++ b/2026/08/29/给一台Linux笔记本做服务器化改造：休眠、充电上限与EC寄存器考古/index.html @@ -192,26 +192,29 @@ </div> </div> <div class="post-content"> - <p>一台退役笔记本装载 Hermes Agent 后转为 7×24 常驻服务器，出厂的笔记本形态留下三类故障：拔电半小时后自动休眠、合盖即失联、电池持续充至满电。本文记录改造全程。前两项属常规配置；第三项在 Linux 下无现成驱动，需要从主板固件代码中定位充电上限的寄存器地址并写入硬件，构成本文主体。</p> -<p>改造对象为 Redmi Book Pro 15 2022，系统 Pop!_OS 24.04，内核 6.18.7。关键步骤均附可复核证据，脚本清单见文末。</p> + <p>一台退役笔记本装载 Hermes Agent 后转为 7×24 常驻服务器，笔记本的默认行为与服务器角色有三处冲突：电源管理在拔电半小时后自动休眠、合盖即失联、充电不设上限。这些是厂商为移动场景设计的合理默认值，对服务器却是故障。本文记录改造全程。前两项属常规配置；第三项在 Linux 下无现成驱动，需要从主板固件代码中定位充电上限的寄存器地址并写入硬件，构成本文主体。</p> +<p>改造对象为 Redmi Book Pro 15 2022，系统 Pop!_OS 24.04，内核 6.18.7。所有脚本完整源码收录于正文。</p> <h2 id="自动休眠由两套机制叠加控制，仅修改其一必然复发"><a class="header-anchor" href="#自动休眠由两套机制叠加控制，仅修改其一必然复发">¶</a>自动休眠由两套机制叠加控制，仅修改其一必然复发</h2> <p>第一处位于 GNOME 会话。<code>org.gnome.settings-daemon.plugins.power</code> 键值组区分供电与电池两种策略，该机出厂默认前者为 <code>nothing</code>（不休眠）、后者为 <code>suspend</code>（30 分钟无操作休眠）。服务器拔电即失联，直接原因即电池策略。修改两条键值即可禁用：</p> <figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">gsettings <span class="built_in">set</span> org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type <span class="string">'nothing'</span></span><br><span class="line">gsettings <span class="built_in">set</span> org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type <span class="string">'nothing'</span></span><br></pre></td></tr></table></figure> -<p>第二处位于 systemd-logind。不处理它，合盖仍触发 suspend。向 <code>/etc/systemd/logind.conf.d/</code> 写入 drop-in 配置：</p> +<p>第二处位于 systemd-logind。不处理它，合盖仍触发 suspend。向 <code>/etc/systemd/logind.conf.d/99-server-nosuspend.conf</code> 写入 drop-in 配置：</p> <figure class="highlight ini"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="section">[Login]</span></span><br><span class="line"><span class="attr">HandleLidSwitch</span>=ignore</span><br><span class="line"><span class="attr">HandleLidSwitchExternalPower</span>=ignore</span><br><span class="line"><span class="attr">HandleLidSwitchDocked</span>=ignore</span><br><span class="line"><span class="attr">AllowSuspend</span>=<span class="literal">no</span></span><br><span class="line"><span class="attr">AllowHibernation</span>=<span class="literal">no</span></span><br></pre></td></tr></table></figure> <p><code>AllowSuspend=no</code> 与 <code>AllowHibernation=no</code> 使 suspend、hibernate 两个 systemd 目标在系统层不可达：任何组件发起休眠请求，systemd 直接拒绝执行。这一层保证无论用户会话如何变更，服务器不会被睡掉。</p> +<p>上述配置对应脚本 <code>setup-server-power.sh</code>，其主体即本节三条命令加上 logind 重启，此处不再展开。</p> <h2 id="充电上限配置存在两年，从未生效"><a class="header-anchor" href="#充电上限配置存在两年，从未生效">¶</a>充电上限配置存在两年，从未生效</h2> <p>机器长期安装 TLP，配置如下：</p> <figure class="highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">START_CHARGE_THRESH_BAT0=20</span><br><span class="line">STOP_CHARGE_THRESH_BAT0=80</span><br></pre></td></tr></table></figure> <p>电量仍充至 94%（衰减后的实际满充点）。TLP 自身不操作硬件，仅调用内核接口。内核标准接口为 <code>/sys/class/power_supply/BAT0/charge_control_end_threshold</code>；TLP 依次探测三种后端：<code>natacpi</code>（内核 ACPI 驱动直写）、<code>acpi_call</code>（第三方模块调用任意 ACPI 方法）、<code>sysfs</code>（上述标准接口）。三种后端在本机全部缺失：Redmi 未向内核提交任何 EC 驱动，<code>charge_control_end_threshold</code> 不存在，<code>acpi_call</code> 未安装。</p> -<p>TLP 对后端缺失的处理是静默降级：保留配置，不执行任何操作。此即"设置了上限却充到满"的完整成因。</p> +<p>TLP 对后端缺失的处理是静默降级：保留配置，不执行任何操作。此即"设置了上限却充到满"的完整成因。补装 <code>acpi-call-dkms</code> 后重启 TLP，<code>tlp-stat</code> 报告 <code>natacpi (system76_acpi) = inactive (laptop not supported)</code>，阈值接口依旧未出现——ACPI 层无方法可调，此路不通。</p> <h2 id="从-DSDT-定位-EC-充电上限字段"><a class="header-anchor" href="#从-DSDT-定位-EC-充电上限字段">¶</a>从 DSDT 定位 EC 充电上限字段</h2> <p>内核不提供接口时，固件代码是唯一可靠的文档。ACPI 的 DSDT 表是主板固件的 AML 执行代码，用 <code>iasl</code> 反汇编后可检索：</p> <figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="built_in">cp</span> /sys/firmware/acpi/tables/DSDT /tmp/probe/</span><br><span class="line">iasl -d /tmp/probe/DSDT.bin</span><br></pre></td></tr></table></figure> <p>反汇编产物中，<code>Device (EC0)</code> 即嵌入式控制器（Embedded Controller，主板上管理电池、键盘、风扇等底层事务的 8 位单片机）。EC 向 ACPI 暴露的字段表以 <code>Field (ERAM…)</code> 开头，逐项列出字段名与位宽。检索电池相关命名，得到关键结构：</p> <figure class="highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><span class="line">Offset (0x80),</span><br><span class="line">ACIN, 1, // AC 已插电</span><br><span class="line">BTIN, 1, // 电池在位</span><br><span class="line">BTST, 4, // 电池状态</span><br><span class="line">ADPW, 8,</span><br><span class="line">BTSN, 16, // 序列号</span><br><span class="line">BTDC, 16, // Design Capacity 设计容量</span><br><span class="line">BTDV, 16, // Design Voltage 设计电压</span><br><span class="line">BTFC, 16, // Full Charge Capacity 满充容量</span><br><span class="line">BTTP, 16,</span><br><span class="line">BTCT, 16, // Cycle Count 循环次数</span><br><span class="line">BTPR, 16, // Present Capacity 当前容量</span><br><span class="line">BTVT, 16, // Voltage 电压</span><br><span class="line">RSOC, 8, // Relative State of Charge 电量百分比</span><br><span class="line">… // 8 个状态位占满一个字节</span><br><span class="line">BTCC, 16, // Charge Cap 充电上限</span><br><span class="line">BATM, 16,</span><br></pre></td></tr></table></figure> <p>依据 ACPI Field 的位累积规则逐字段推算，各字段在 EC RAM 中的字节位置随之确定：电量百分比 RSOC 位于偏移 0x92，充电上限 BTCC 位于 0x95-0x96（16 位小端）。本机 EC RAM 经内存映射窗口 <code>0xFE0B0400</code> 可直接访问。</p> -<p>偏移推算须经读取验证。一次读出 32 字节，与系统已知值交叉比对：</p> +<p>偏移推算须经读取验证。验证脚本用 <code>dd</code> 从 <code>/dev/mem</code> 读出窗口内 32 字节，再按偏移表逐字段解码：</p> +<figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#!/bin/bash</span></span><br><span class="line"><span class="comment"># ec-verify-readonly.sh — 只读验证偏移表，不做任何写入</span></span><br><span class="line">[ <span class="string">"<span class="subst">$(id -u)</span>"</span> -eq 0 ] || { <span class="built_in">echo</span> <span class="string">"请用 sudo 运行"</span>; <span class="built_in">exit</span> 1; }</span><br><span class="line"><span class="built_in">dd</span> <span class="keyword">if</span>=/dev/mem bs=1 skip=$((<span class="number">0</span>xFE0B0480)) count=32 of=/tmp/ec-read.bin status=none</span><br><span class="line">python3 - <<<span class="string">'PYEOF'</span></span><br><span class="line">data = open(<span class="string">"/tmp/ec-read.bin"</span>,<span class="string">"rb"</span>).<span class="built_in">read</span>()</span><br><span class="line">def u8(o): <span class="built_in">return</span> data[o]</span><br><span class="line">def u16(o): <span class="built_in">return</span> data[o] | (data[o+1] << <span class="string">8)</span></span><br><span class="line"><span class="string">b80 = data[0]</span></span><br><span class="line"><span class="string">print(f"ACIN(AC插电) = {b80 & 1} (期望 1)")</span></span><br><span class="line"><span class="string">print(f"BTDC 0x84 = {u16(4)} mAh (对照 energy_full_design/电压)")</span></span><br><span class="line"><span class="string">print(f"BTDV 0x86 = {u16(6)} mV (期望约 15440)")</span></span><br><span class="line"><span class="string">print(f"BTFC 0x88 = {u16(8</span>)} mAh (对照 energy_full)<span class="string">")</span></span><br><span class="line"><span class="string">print(f"</span>BTPR 0x8E = {u16(14)} mAh (对照当前容量)<span class="string">")</span></span><br><span class="line"><span class="string">print(f"</span>BTVT 0x90 = {u16(16)} mV (期望 16000-16800)<span class="string">")</span></span><br><span class="line"><span class="string">print(f"</span>RSOC 0x92 = {u8(18)}% (对照 upower 实时值)<span class="string">")</span></span><br><span class="line"><span class="string">print(f"</span>BTCC 0x95 = {u16(21)}% (充电上限，验证目标)<span class="string">")</span></span><br><span class="line"><span class="string">print(f"</span>BTCT 0x8C = {u16(12)} 次 (循环次数)<span class="string">")</span></span><br><span class="line"><span class="string">PYEOF</span></span><br></pre></td></tr></table></figure> +<p>一次读出 32 字节，与系统已知值交叉比对：</p> <table> <thead> <tr> @@ -257,8 +260,12 @@ <p>五项独立指标全部命中，偏移表成立。读取同时得到一项内核长期隐瞒的数据：循环次数 1196 次——sysfs 的 <code>cycle_count</code> 一直报 0，真实值存于 EC。84.5% 的健康度对应一千二百次循环，衰减幅度在正常区间；80% 上限将显著延缓后续衰减。</p> <p>首次读取时 BTCC 为 0：该字段从未被任何系统写入过。TLP 静默失效，小米管理软件从未在 Linux 侧运行，此字段空置两年。</p> <h2 id="写入与开机固化"><a class="header-anchor" href="#写入与开机固化">¶</a>写入与开机固化</h2> -<p>写入是针对内存映射窗口的 2 字节操作：<code>dd</code> 定位 <code>0xFE0B0495</code>，写入小端编码的 80，读回确认。行为验证给出更强的证据：写入时电量 87%，高于上限，电池状态立即转为 Discharging；电量自然回落至 83% 后状态转为 Charging。EC 严格执行"低于 80 充电、达到 80 停充"。</p> -<p>EC 值可能在冷启动后复位，需开机重写。方案为 oneshot 型 systemd 服务（<code>WantedBy=multi-user.target</code>），执行 20 行 shell 脚本：写入、至多 5 次读回重试、结果写 syslog。验证一行命令：<code>journalctl -t ec-charge-limit</code>。</p> +<p>写入是针对内存映射窗口的 2 字节操作。写入时电量 87%，高于上限，电池状态立即转为 Discharging；电量自然回落至 83% 后状态转为 Charging。EC 严格执行"低于 80 充电、达到 80 停充"。</p> +<p>EC 值可能在冷启动后复位，需开机重写。方案为 oneshot 型 systemd 服务，执行 18 行运行时脚本 <code>/usr/local/bin/ec-charge-limit</code>——这是全套配置中唯一长期驻留的代码，全文如下：</p> +<figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#!/bin/bash</span></span><br><span class="line"><span class="comment"># ec-charge-limit — BTCC @ 0xFE0B0495 (little-endian u16)</span></span><br><span class="line"><span class="comment"># 用法: ec-charge-limit [20-100]，由 ec-charge-limit.service 开机调用</span></span><br><span class="line">LIMIT=<span class="variable">${1:-80}</span></span><br><span class="line">[ <span class="string">"<span class="variable">$LIMIT</span>"</span> -ge 20 ] && [ <span class="string">"<span class="variable">$LIMIT</span>"</span> -le 100 ] || <span class="built_in">exit</span> 1</span><br><span class="line">BASE=$((<span class="number">0</span>xFE0B0400)); OFF=$((<span class="number">0</span>x95))</span><br><span class="line">[ <span class="string">"<span class="subst">$(id -u)</span>"</span> -eq 0 ] || <span class="built_in">exit</span> 1</span><br><span class="line"><span class="keyword">for</span> i <span class="keyword">in</span> 1 2 3 4 5; <span class="keyword">do</span></span><br><span class="line"> <span class="built_in">printf</span> <span class="string">"<span class="subst">$(printf '\\x%02x\\x00' <span class="string">"<span class="variable">$LIMIT</span>"</span>)</span>"</span> \</span><br><span class="line"> | <span class="built_in">dd</span> of=/dev/mem bs=1 seek=$((BASE + OFF)) count=2 conv=notrunc status=none \</span><br><span class="line"> || { <span class="built_in">sleep</span> 2; <span class="built_in">continue</span>; }</span><br><span class="line"> <span class="built_in">sleep</span> 1</span><br><span class="line"> <span class="built_in">dd</span> <span class="keyword">if</span>=/dev/mem bs=1 skip=$((BASE + OFF)) count=2 of=/tmp/.btcc-check status=none</span><br><span class="line"> V=$(python3 -c <span class="string">"d=open('/tmp/.btcc-check','rb').read(); print(d[0]|(d[1]<<8))"</span>)</span><br><span class="line"> [ <span class="string">"<span class="variable">$V</span>"</span> = <span class="string">"<span class="variable">$LIMIT</span>"</span> ] && { logger -t ec-charge-limit <span class="string">"BTCC set to <span class="variable">$LIMIT</span> (attempt <span class="variable">$i</span>)"</span>; <span class="built_in">exit</span> 0; }</span><br><span class="line"> <span class="built_in">sleep</span> 2</span><br><span class="line"><span class="keyword">done</span></span><br><span class="line">logger -t ec-charge-limit <span class="string">"FAILED to set BTCC=<span class="variable">$LIMIT</span> after 5 attempts"</span></span><br><span class="line"><span class="built_in">exit</span> 1</span><br></pre></td></tr></table></figure> +<p>脚本包含三重保护：参数限制在 20-100；写入后读回比对，不匹配则重试；至多 5 次，失败写 syslog 并以非零码退出。服务单元 5 行：</p> +<figure class="highlight ini"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line"><span class="section">[Unit]</span></span><br><span class="line"><span class="attr">Description</span>=Set Redmi Book Pro charge limit to <span class="number">80</span>% via EC memory window</span><br><span class="line"><span class="attr">After</span>=multi-user.target</span><br><span class="line"></span><br><span class="line"><span class="section">[Service]</span></span><br><span class="line"><span class="attr">Type</span>=<span class="literal">on</span>eshot</span><br><span class="line"><span class="attr">ExecStart</span>=/usr/local/bin/ec-charge-limit <span class="number">80</span></span><br><span class="line"><span class="attr">RemainAfterExit</span>=<span class="literal">yes</span></span><br><span class="line"></span><br><span class="line"><span class="section">[Install]</span></span><br><span class="line"><span class="attr">WantedBy</span>=multi-user.target</span><br></pre></td></tr></table></figure> +<p>部署后验证：<code>journalctl -t ec-charge-limit</code> 应含 <code>BTCC set to 80 (attempt 1)</code>。</p> <h2 id="方法论：固件代码是最后的文档"><a class="header-anchor" href="#方法论：固件代码是最后的文档">¶</a>方法论：固件代码是最后的文档</h2> <p>TLP 配置存在而从未生效，根源在于用户态工具依赖内核 ABI 的覆盖面。内核接口缺失时，<code>acpi_call</code> 一类通用调用器是第一层补救，但其前提仍是 ACPI 层存在可调用的方法。DSDT 反汇编显示本机 EC 声明了 BTCC 字段，而全部 AML 代码均未读写它：小米将充电控制实现为纯 EC 寄存器协议，仅 Windows 侧私有驱动知晓协议细节。这一层 acpi_call 无法覆盖，剩余路径只有直接读写 EC RAM。</p> <p>直接写 EC 有真实风险：该内存窗口同时被固件自身使用，写错偏移可能影响风扇、键盘背光乃至供电策略。本次风险控制依赖三项措施：写入前完成只读交叉验证，五项指标全部命中后才执行写入；写入范围收窄至 2 字节；写入后立即读回并观察充电行为。回滚与写入同路：向同一地址写 100 即恢复满充。</p> @@ -269,7 +276,7 @@ <li>开机自动重写上限，冷启动不丢配置</li> <li>电池档案：设计 72 Wh，满充 60.8 Wh（健康度 84.5%），循环 1196 次</li> </ul> -<p>脚本归档：<code>setup-server-power.sh</code>（休眠禁用）、<code>acpi-probe-battery.sh</code>（DSDT 反汇编与只读探测）、<code>ec-verify-readonly.sh</code>（字段交叉验证）、<code>ec-set-charge-limit.sh</code>（写入与行为观察）、<code>power-rollback.sh</code>（一键回滚）。其他"EC 沉默"的机型可直接复用该流程：先以只读交叉验证证明地址表，再执行写入。</p> +<p>辅助脚本归档于本地（篇幅所限未全文收录）：<code>setup-server-power.sh</code>（休眠禁用，含备份与逐步回显）、<code>acpi-probe-battery.sh</code>（DSDT 反汇编与 ACPI 只读探测）、<code>ec-set-charge-limit.sh</code>（首次写入与 60 秒行为观察）、<code>power-rollback.sh</code>（一键回滚）。其他"EC 沉默"的机型可直接复用核心流程：反汇编 DSDT 检索字段表 → 手工推算偏移 → 只读交叉验证 → 验证命中后再写入。</p> </div> |