Re: [BUG] Stuck key syndrome (was: Re: [PATCH net-next v2] net: dsa: microchip: Add SGMII port support to KSZ9477 switch)

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

On Wed, 7 May 2025 12:44:24 +0100
"Russell King (Oracle)" <linux@armlinux.org.uk> wrote:

> Hi Maxime,
> 
> On Wed, May 07, 2025 at 03:32:36PM +0200, Maxime Chevallier wrote:
> > Hi Russell,
> > 
> > On Wed, 7 May 2025 10:59:21 +0100
> > "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:
> >   
> > > On Wed, May 07, 2025 at 10:23:17AM +0100, Russell King (Oracle) wrote:  
> > > > [Sorry for going off topic here - changed the Cc list, added Linus,
> > > > changed the subject.]
> > > > 
> > > > On Wed, May 07, 2025 at 10:54:57AM +0200, Maxime Chevallier wrote:    
> > > > > On Wed, 7 May 2025 09:31:48 +0100
> > > > > "Russell King (Oracle)" <linux@armlinux.org.uk> wrote:    
> > > > > > [rest of the email got deleted because Linux / X11 / KDE got confused
> > > > > > about the state the backspace key and decided it was going to be
> > > > > > continuously pressed and doing nothing except shutting the laptop
> > > > > > down would stop it.]    
> > > > > 
> > > > > Funny how I have the same exact issue on my laptop as well...     
> > > > 
> > > > I've had the "stuck key" behaviour with the HP Pavilion 15-au185sa
> > > > laptop I had previously (normally with ctrl-F keys). However, hitting
> > > > ctrl/shift/alt would stop it.
> > > > 
> > > > This is the first time I've seen the behaviour with the Carbon X1
> > > > laptop, but this was way more severe. No key would stop it. Trying to
> > > > move the focus using the trackpad/nipple had any effect. Meanwhile
> > > > the email was being deleted one character at a time. So I shut the
> > > > laptop lid causing it to suspend, and wondered what to do... on
> > > > re-opening the laptop, it didn't restart and is back to normal.
> > > > 
> > > > This suggests that the entire input subsystem in the software stack
> > > > collapsed just after the backspace key was pressed, and Xorg never
> > > > saw the key-release event. So Xorg duitifully did its key-repeat
> > > > processing, causing the email to be deleted one character at a time.
> > > > 
> > > > The problem is, not only did this destroy the email reply, but it
> > > > also destroyed my train of thought for the reply as well through
> > > > the panic of trying to stop the entire email being deleted.
> > > > 
> > > > I don't think this is a hardware issue - I think there's a problem
> > > > in the input handling somewhere in the stack of kernel, Xorg,
> > > > whatever multiple input libraries make up modern systems, and KDE.
> > > > 
> > > > I did check the logs. Nothing in the kernel messages that suggests
> > > > a problem. Nothing in Xorg's logs (which are difficult to tie up
> > > > because it doesn't use real timestamps that one can relate to real
> > > > time.) There's no longer any ~/.xsession-errors logfile for logging
> > > > the stuff below Xorg.
> > > > 
> > > > I'm running Debian Stable here - kernel 6.1.0-34-amd64, X.Org X Server
> > > > 1.21.1.7, KDE Plasma (5.27.5, frameworks 5.103.0, QT 5.15.8).    
> > > 
> > > I'll also add that The Carbon X1, being a laptop, its built-in keyboard
> > > uses the i8042:
> > > 
> > > [    1.698156] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
> > > [    1.698543] i8042: Warning: Keylock active
> > > [    1.700170] serio: i8042 KBD port at 0x60,0x64 irq 1
> > > [    1.700174] serio: i8042 AUX port at 0x60,0x64 irq 12
> > > [    1.700271] mousedev: PS/2 mouse device common for all mice
> > > [    1.702951] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input0
> > > 
> > > I don't have the HP laptop with me to check what that was using.
> > > 
> > > The mysterious thing is "Keylock active" - clearly it isn't because I
> > > can write this email typing on that very keyboard. However, I wonder
> > > if it needs i8042_unlock=1 to set I8042_CTR_IGNKEYLOCK.
> > > 
> > > Unfortunately, it's probably going to take a year on the Carbon X1
> > > to work out if this makes any difference.
> > >  
> > > > Anyone else seeing this kind of behaviour - if so, what are you
> > > > using?  
> > 
> > It just happened to me as I was typing this very email (key 'd' got
> > stuck, nothing could un-stick it, couldn't move the mouse cursor but
> > mouse-click events did work, had to suspend/resume the laptop to fix
> > that)  
> 
> 'd' can be quite disastrous if you're using vi and you're in command
> mode!
> 
> > Got the same "Keylock active" warning at boot :
> > 
> > [    0.916750] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:PS2M] at 0x60,0x64 irq 1,12
> > [    0.917210] i8042: Warning: Keylock active
> > [    0.920087] serio: i8042 KBD port at 0x60,0x64 irq 1
> > [    0.920090] serio: i8042 AUX port at 0x60,0x64 irq 12
> > 
> > Nothing in the kernel logs when the key got stuck.
> > 
> > Laptop is a Dell XPS 15 9510, Running Fedora 41 but I saw this issue
> > before, kernel 6.14.4-200.fc41.x86_64, Wayland-based, Gnome 47.
> > 
> > Hopefully this helps a bit narrowing this down, I have a fairly
> > different userspace stack and kernel version, but we do have the same
> > driver involved and same keylock warning...  
> 
> Could you try booting with i8042_unlock=1 and see whether that makes any
> difference please?

I'll try this out indeed :)

> I've added that to my grub config in preparation for rebooting, but even
> if I booted now, I suspect it'll be some time before I have any useful
> result.
> 
> How often do you see the problem?

It's very sporadic, sometimes I'll see this behaviour multiple times a
day, and then nothing for weeks... This laptop has been very quirky
ever since I got it, so I categorized that as a "yet another XPS 9510
broken behaviour", but this has been a recurrent thing for multiple
years...

So, same as you, it'll take a long time for me to say with some amount
of certainty that 'i8042_unlock=1' has a beneficial effect, of
course unless I see the problem happen again in the meantime.

Maxime