• lianzhi chang's avatar
    tty: Fix the keyboard led light display problem · fb09d0ac
    lianzhi chang authored
    
    
    Use the "ctrl+alt+Fn" key combination to switch the system from tty to
    desktop or switch the system from desktop to tty. After the switch is
    completed, it is found that the state of the keyboard lock is
    inconsistent with the state of the keyboard Led light.The reasons are
    as follows:
    
    * The desktop environment (Xorg and other services) is bound to a tty
      (assuming it is tty1), and the kb->kbdmode attribute value of tty1
      will be set to VC_OFF. According to the current code logic, in the
      desktop environment, the values of ledstate and kb->ledflagstate
      of tty1 will not be modified anymore, so they are always 0.
    
    * When switching between each tty, the final value of ledstate set by
      the previous tty is compared with the kb->ledflagstate value of the
      current tty to determine whether to set the state of the keyboard
      light. The process of switching between desktop and tty is also the
      process of switching between tty1 and other ttys. There are two
      situations:
    
      - (1) In the desktop environment, tty1 will not set the ledstate,
      which will cause when switching from the desktop to other ttys,
      if the desktop lights up the keyboard's led, after the switch is
      completed, the keyboard's led light will always be on;
    
      - (2) When switching from another tty to the desktop, this
      mechanism will trigger tty1 to set the led state. If other tty
      lights up the led of the keyboard before switching to the desktop,
      the led will be forcibly turned off. This situation should
      be avoided.
    
    * The current patch is to solve these problems: When VT is switched,
      the keyboard led needs to be set once.Ensure that after the
      switch is completed, the state of the keyboard LED is consistent
      with the state of the keyboard lock.
    Suggested-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    Reviewed-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    Signed-off-by: default avatarlianzhi chang <changlianzhi@uniontech.com>
    Link: https://lore.kernel.org/r/20211215125125.10554-1-changlianzhi@uniontech.com
    
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    fb09d0ac
keyboard.c 52.8 KB