Messages in this thread | | | Date | Fri, 24 Jan 2014 08:52:02 -0800 | Subject | Re: Keyboard dead for a bunch of LG laptops | From | Shawn N <> |
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Thanks for the bug report + bisect.
On Fri, Jan 24, 2014 at 8:21 AM, Joonas Saarinen <jza@saunalahti.fi> wrote: > Hello, people! There's still lingering an interesting regression where the > internal keyboard of various older LG laptops is dead. It is tracked here: > > https://bugzilla.kernel.org/show_bug.cgi?id=58991 > > Downstream: > https://bugzilla.redhat.com/show_bug.cgi?id=969550 > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1243904 > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1256776 > > Late last year, I personally did a git bisect on LG LW25 which ended up > pointing at an atkbd patch: > > be2d7e4233a4fe439125b825470020cef83407d5 > Input: atkbd - fix multi-byte scancode handling on reconnect > > Full description about that patch and some discussion: > https://groups.google.com/forum/#!topic/fa.linux.kernel/rUpZ8-HaQIM > > Could it be that? The boot parameter i8042.dumbkbd=1 can be used to still > make the keyboard functional. Of course that workaround leaves the keyboard > a bit gimped (no lock LEDs, for example). > > So, some questions: > > 1) What exactly happened? Is there something common with these LG machines' > BIOS or keyboard controller firmware which causes the problem? >
It's hard to guess, it seems like a bug / quirk of the KB controller implementation. It looks like ATKBD_CMD_ENABLE is not re-enabling the keyboard after ATKBD_CMD_RESET_DIS is received. I will try to acquire a LG LW25 laptop to debug.
> 2) How could this happen? I thought the i8042 keyboard was one of the > simplest devices in a PC. It's quite serious if it stops working like this. >
There are many independent KB controller implementations that use this driver, each with different bugs / quirks. It's the danger of modifying such a widely-used driver.
> 3) Should something be done? Those are of course aging (Core 1 Duo era) > machines, but I think Linux has always strived to work well with all sorts > of hardware, old and new. >
I'm not sure what to do here, I will leave the decision to "management" whether to revert. Meanwhile, I will acquire an LG laptop that demonstrates this problem, and debug to get a better idea about the failure case.
> > Joonas
Shawn
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