我在 MacBook Air 5,2(2012 年中,13 英寸)上使用 14.04。我最近才注意到动力顶列出内置读卡器以消耗大量电量:
Power est. Usage Device name
6.68 W 100,0% USB device: Card Reader (Apple)
399 mW 2,9% CPU core
235 mW 3,9 ops/s GPU core
90.2 mW 3,9 ops/s GPU misc
0 mW 100,0% USB device: usb-device-8087-0024
0 mW 100,0% USB device: EHCI Host Controller
我已将所有 USB 设备设置为省电模式rc.本地:
# WLAN
iw dev wlan0 set power_save on;
# PCI general powersaving
for pci in /sys/bus/pci/devices/*/power/control;
do echo auto > $pci;
done
# USB general powersaving
for usb in /sys/bus/usb/devices/*/power/control;
do echo auto > $usb;
done
# NMI watchdog
echo '0' > '/proc/sys/kernel/nmi_watchdog';
# backlight
echo '3' > '/sys/class/backlight/acpi_video0/brightness';
exit 0
通过终端检查时,似乎省电功能已正确启用:
$ cat /sys/bus/usb/devices/2-1.8.3/idVendor
05ac
$ cat /sys/bus/usb/devices/2-1.8.3/idProduct
8404
$ lsusb | grep 8404
Bus 002 Device 006: ID 05ac:8404 Apple, Inc. Internal Memory Card Reader
$ cat /sys/bus/usb/devices/2-1.8.3/power/control
auto
$ cat /sys/bus/usb/devices/2-1.8.3/power/autosuspend
2
安装 14.04 后没有注意到这一点。可能是一些内核更新。读卡器在文件管理器中仍能正常工作,但现在不断耗电。有什么想法吗?