device.led（）后的grab（）关闭led

Question

我可以使用evdev读取NUML\u的LED状态。但是，如果我在退出程序时读取led后抓取（）设备，led将关闭，即使系统的状态仍为打开

import evdev

device = evdev.InputDevice('/dev/input/event3')

try:
    print(device.leds(verbose=True))
    print("Using device:\n" + str(device))
    device.grab()
except  (KeyboardInterrupt, SystemExit):
    pass

如果我只做grab()或device.leds()中的一个而不做另一个，它们（如预期的那样）不会关闭。但调用这两个都会使LED出现问题

编辑： 我刚刚意识到，如果LED\ NUML和LED\ CAPSL在我退出时打开，则LED熄灭，但当我按下num\ U lock或caps\ U lock时，另一个按钮的状态也会得到修复

即：

- LED_NUML and LED_CAPSL are on
- run script
- LED_NUML and LED_CAPSL are off
- press num_lock turns num_lock off (LED_NUML is already off so it stays off)
- LED_CAPSL turns on

Answer 1

在这个时候是不可能的。内核中有一个问题。正如ssieb在python evdev问题页面about this issue上所说的那样

When a device is released, all handlers attached to the device get restarted. My guess is that there is some handler that is resetting the LEDs.