Re: git: ce881170088c - main - atkbd: Disable periodic polling by default.

From: Gleb Smirnoff <glebius_at_freebsd.org>
Date: Thu, 06 Jan 2022 00:04:28 UTC
On Wed, Jan 05, 2022 at 04:18:25PM -0700, Warner Losh wrote:
W> On Wed, Jan 5, 2022, 3:47 PM Gleb Smirnoff <glebius@freebsd.org> wrote:
W> 
W> > On Wed, Jan 05, 2022 at 08:13:03PM +0000, Alexander Motin wrote:
W> > A> commit ce881170088c4c98c036fe561f8ee8413c2e2585
W> > A> Author:     Alexander Motin <mav@FreeBSD.org>
W> > A> AuthorDate: 2022-01-05 20:00:36 +0000
W> > A> Commit:     Alexander Motin <mav@FreeBSD.org>
W> > A> CommitDate: 2022-01-05 20:12:58 +0000
W> > A>
W> > A>     atkbd: Disable periodic polling by default.
W> > A>
W> > A>     It is one of the few remaining Giant-locked callouts.  It would be
W> > A>     good to remove it, not mentioning that polling itself is not good.
W> > A>
W> > A>     If this cause keyboard/mouse freezes on some hardware, please set
W> > A>     loader tunable hw.atkbd.hz=1 as workaround and report the issue.
W> > A>
W> > A>     Submitted by:   imp, jhb
W> >
W> > Lame question: this is related only to a keyboard plugged into PS/2, isn't
W> 
W> Yes. I think this part of the code is only for "legacy" keyboards. I don't
W> think mice are affected, but since both attach to the keyboard controller
W> there is a tiny chance mice might be affected in some weird hardware...

I'd even say to legacy mainboards. Cause I have PS/2 keybooard plugged into
USB port and AFAIU it is not affected by this change in any way.

I think that even if this change creates some regression, we never know that.
Nobody would today run so old mainboard as a desktop. Might have it as a
headless appliance.

-- 
Gleb Smirnoff