From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: Thinkpad t410 does not reboot properly
To: Walter Alejandro Iglesias <wai@roquesor.com>, tech@openbsd.org
Date: Wed, 05 Jun 2024 07:42:28 -0600

Stuart Henderson <stu@spacehopper.org> wrote:

> On 2024/06/05 04:42, Crystal Kolipe wrote:
> > On Wed, Jun 05, 2024 at 09:06:41AM +0200, Walter Alejandro Iglesias wrote:
> > > Running halt -p the machine powers off perfectly but running reboot at
> > > the last moment in the halt process (screen already turned off) the
> > > machine does not turn off, it hangs indefinitely, I have to press the
> > > power button manually to turn it off.
> > 
> > I've also seen this behaviour from time to time on a Thinkpad X260 so the
> > underlying problem is probably not specific to your machine.
> 
> X260 has always been problematic with reboots, not 100% of the time (in
> particular a reboot shortly after boot seems more likely to work) but
> very often. The only thing I've seen that improved things there is
> kettenis' "EFI runtime services on amd64" diff.

On two machines with such a problem I've seen that if I disable the
umb(4) in the BIOS, it reboots fine.