为什么运行时电源管理在切换到主电源时会从“好”切换到“坏”？

Question

作为背景，我试图了解为什么我的笔记本电脑总是有它的风扇运行时，在交流电源。

我安装并运行了powertop工具。

我注意到，当我从电池电源切换到电源时，powertop显示的各种“可调”项目从“好”切换到“坏”。

我的问题是:为什么powertop可调项目从“好”切换到“坏”时从电池切换到电源？

(...and，这能解释为什么风扇总是开着吗？)

笔记本电脑是一个戴尔的精度5520，运行Ubuntu20.04。安装了电池电源管理实用程序tlp。

作为进一步的详细信息，以下是powertop的tuneables选项卡在AC电源上运行时列出的内容：

>> Bad           Enable SATA link power management for host0                                                            
   Bad           Enable SATA link power management for host1
   Bad           Enable Audio codec power management
   Bad           Runtime PM for I2C Adapter i2c-5 (i915 gmbus dpd)
   Bad           Runtime PM for I2C Adapter i2c-0 (SMBus I801 adapter at f040)
   Bad           Runtime PM for I2C Adapter i2c-3 (i915 gmbus dpc)
   Bad           Runtime PM for I2C Adapter i2c-4 (i915 gmbus dpb)
   Bad           Runtime PM for PCI Device Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family SMBus
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller
   Bad           Runtime PM for PCI Device Intel Corporation HD Graphics 630
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family Serial IO I2C Controller #0
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem
   Bad           Runtime PM for PCI Device Intel Corporation CM238 HD Audio Controller
   Bad           Runtime PM for PCI Device Intel Corporation Wireless 8265 / 8275
   Bad           Runtime PM for PCI Device Intel Corporation CM238 Chipset LPC/eSPI Controller
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family Serial IO I2C Controller #1
   Bad           Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family Power Management Controller
   Bad           Runtime PM for PCI Device Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader
   Bad           Runtime PM for PCI Device Intel Corporation Q170/Q150/B150/H170/H110/Z170/CM236 Chipset SATA Controller [AHCI Mode]
   Bad           Runtime PM for PCI Device Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers
   Good          NMI watchdog should be turned off
   Good          VM writeback timeout
   Good          Bluetooth device interface status
   Good          Runtime PM for I2C Adapter i2c-2 (Synopsys DesignWare I2C adapter)
   Good          Autosuspend for USB device Integrated_Webcam_HD [CN045G28LOG00815B9B6A01]
   Good          Runtime PM for I2C Adapter i2c-1 (Synopsys DesignWare I2C adapter)
   Good          Autosuspend for USB device xHCI Host Controller [usb1]
   Good          Autosuspend for unknown USB device 1-4 (8087:0a2b)
   Good          Autosuspend for USB device xHCI Host Controller [usb2]
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #1
   Good          Runtime PM for port ata1 of PCI device: Intel Corporation Q170/Q150/B150/H170/H110/Z170/CM236 Chipset SATA Controller [AHCI Mode]
   Good          Runtime PM for PCI Device Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16)
   Good          Runtime PM for port ata2 of PCI device: Intel Corporation Q170/Q150/B150/H170/H110/Z170/CM236 Chipset SATA Controller [AHCI Mode]
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family MEI Controller #1
   Good          Runtime PM for disk sda
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #9
   Good          Runtime PM for PCI Device NVIDIA Corporation GM107GLM [Quadro M1200 Mobile]
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #13
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #15
   Good          Runtime PM for PCI Device Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #2

前面的一个问题(参见这里)在探索粉丝的类似问题时提到了powertop工具。

Answer 1

因为TLP使用两个设置配置文件，它们根据电源自动应用：

• 当AC连接时，以_AC结尾的参数是有效的
• 以_BAT结尾的参数在电池上运行时是有效的。

但这当然可以配置。

如果您希望AC的设置与电池模式相同，那么您可以调整配置(in /etc/tlp.conf)如下：

TLP_DEFAULT_MODE=BAT
TLP_PERSISTENT_DEFAULT=1

相反，您还可以调整单个设置，例如Runtime：

RUNTIME_PM_ON_AC=auto

详细信息，请参阅文档：

• https://linrunner.de/tlp/introduction.html
• https://linrunner.de/tlp/settings/introduction.html
• https://linrunner.de/tlp/settings/operation.html
• https://linrunner.de/tlp/settings/runtimepm.html
• https://linrunner.de/tlp/faq/powertop.html