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

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Wed, May 07, 2025 at 10:23:37AM -0700, Dmitry Torokhov wrote:
> On Wed, May 07, 2025 at 07:46:03AM -0700, Linus Torvalds wrote:
> > On Wed, 7 May 2025 at 04:51, Maxime Chevallier
> > <maxime.chevallier@bootlin.com> wrote:
> > >
> > > 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.
> > 
> > Christ. You'd expect that any i8042 issues had been fixed long ago,
> > but the problem is that the chip doesn't necessarily even exist in
> > modern platforms, and everybody just fakes it.
> 
> It has not existed as a real chip for more than 20 years I believe. It's
> all faked in firmware and embedded controllers that fake it in their
> firmwares.
> 
> And newer firmware tend to implement less and less of it, just what OS
> that devices that ship with it needs.
> 
> > 
> > So the platform presumably still has hardware support for it, but it's
> > mostly in the form of "take a trap when accessing the legacy keyboard
> > ports, and fake it in firmware".
> > 
> > Although it doesn't help that there are literally decades of clone
> > chips and hacky real hardware that extended on the i8042 in various
> > more-or-less compatible ways.
> > 
> > Which makes all of these things almost entirely undebuggable.
> > 
> > I'm surprised the XPS9510 would be particularly troublesome - I've had
> > an XPS for years (older version, obviously) with no issues outside of
> > WiFi sometimes acting up. But random firmware...
> > 
> > I doubt it's "keylock active", but who knows. I get that on my xps
> > too, it's a random bit that doesn't really mean much. But - because of
> > all the reasons above - who knows...
> 
> It is typically harmless and whats more trying to "unlock" 8042 when it
> reports being locked might confuse 8042 emulation.

So I think the summary of this thread is... laptop keyboards are
unreliable, and it's a lottery whether any particular laptop works
or remains working over firmware updates.

Surely that essentially means, laptops are basically unreliable
devices?

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