linux-kernel - Re: [PATCH v14] tty: Fix the keyboard led light display problem

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Message-ID: <tencent_5573CD56296D5E2F4C59A664@qq.com>
Date:   Thu, 25 Nov 2021 10:33:23 +0800
From:   "lianzhi chang" <changlianzhi@...ontech.com>
To:     "dmitry.torokhov" <dmitry.torokhov@...il.com>
Cc:     "linux-kernel" <linux-kernel@...r.kernel.org>,
        "Greg KH" <gregkh@...uxfoundation.org>,
        "jirislaby" <jirislaby@...nel.org>,
        "Andy Shevchenko" 
        <andriy.shevchenko@...ux.intel.com>,
        "282827961" <282827961@...com>
Subject: Re: [PATCH v14] tty: Fix the keyboard led light display problem

> > On Mon, Nov 08, 2021 at 01:51:39PM +0800, lianzhi chang wrote:
> > > Switching from the desktop environment to the tty environment,
> > > the state of the keyboard led lights and the state of the keyboard
> > > lock are inconsistent. This is because the attribute kb->kbdmode
> > > of the tty bound in the desktop environment (Xorg) is set to
> > > VC_OFF, which causes the ledstate and kb->ledflagstate

> > We know that Xorg sets kbdmode mode to VC_OFF, but it does not mean that
> > you can say for sure that it is Xorg instance that controls a VT simply
> > by observing kb->kbdmode. There may be something else entirely. That is
> > why you want drivers/tty/vt/keyboard.c to reset LEDs and leave it to
> > whoever is controlling VT to set them to something else if it is
> > desired.

> Does this mean let me change the description information? Or is the
> judgment of VC_OFF in patch incorrect?
> The setup method of Xorg mentioned here is just to describe a process
> in which I found the problem;
> My understanding is that when the mode of kbdmode is set to VC_OFF,
> VT shouldn't interfere with the state of the keyboard light, right? This is
> how functions such as kbd_keycode() are implemented.
> When VT is switched, if the VT mode is VC_OFF, there is also no need
> to set the state of the keyboard light. I think this is reasonable.

> > > > values of the bound tty to always be 0, which causes the switch
> > > > from the desktop When to the tty environment, the LED light
> > > > status is inconsistent with the keyboard lock status.
> > > > In order to ensure that the keyboard LED lights are displayed
> > > > normally during the VT switching process, when the VT is
> > > > switched, the current VT LED configuration is forced to be issued.
> > >
> > > Signed-off-by: lianzhi chang <changlianzhi@...ontech.com>
> > > Suggested-by: dmitry.torokhov <dmitry.torokhov@...il.com>
> > > Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > > ---
> > >  v13:
> > >  The kbd_bh function no longer handles the "kb->kbdmode == VC_OFF"
> > >  scene, but puts this process in vt_set_leds_compute_shiftstate
> > >  together. Because the current circumvention is that other ttys
> > >  switch to the Xorg-bound tty scene, so this Better.
> > >  v14:
> > >  Sorry, I forgot to verify the format, it is good now.
> > >
> > >  drivers/tty/vt/keyboard.c | 19 ++++++++++++++++++-
> > >  1 file changed, 18 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
> > > index c7fbbcdcc346..91e1c5d92029 100644
> > > --- a/drivers/tty/vt/keyboard.c
> > > +++ b/drivers/tty/vt/keyboard.c
> > > > @@ -153,6 +153,7 @@ static int shift_state = 0;
> > >
> > >  static unsigned int ledstate = -1U; /* undefined */
> > >  static unsigned char ledioctl;
> > > +static bool vt_switch;
> > >
> > >  /*
> > >   * Notifier list for console keyboard events
> > > @@ -412,9 +413,20 @@ static void do_compute_shiftstate(void)
> > >  /* We still have to export this method to vt.c */
> > >  void vt_set_leds_compute_shiftstate(void)
> > >  {
> > > + struct kbd_struct *kb;
> > >  unsigned long flags;
> > >
> > > - set_leds();
> > > + /* Xorg will bind a tty, the kb->kbdmode of this tty will be set to
> > > + * VC_OFF, and this tty will no longer set the keyboard light. If
> > > + * there is no such restriction, when switching from other tty to
> > > + * Xorg-bound tty, the tty will set the keyboard light, which is
> > > + * unreasonable
> > > + */
> > > + kb = kbd_table + fg_console;
> > > + if (kb->kbdmode != VC_OFF) {
> > > + vt_switch = true;
> > > + set_leds();
> > > + }
> > >
> > >  spin_lock_irqsave(&kbd_event_lock, flags);
> > >  do_compute_shiftstate();
> > > @@ -1255,6 +1267,11 @@ static void kbd_bh(struct tasklet_struct *unused)
> > >  leds |= (unsigned int)kbd->lockstate << 8;
> > >  spin_unlock_irqrestore(&led_lock, flags);
> > >
> > > + if (vt_switch) {
> > > + ledstate = ~leds;
> > > + vt_switch = false;
> > > + }
> > > +
> > >  if (leds != ledstate) {
> > >  kbd_propagate_led_state(ledstate, leds);
> > >  ledstate = leds;
> > > --

Hi friends, how is this patch progressing now, do I need to modify it further?

Thanks.
--
lianzhi chang