Re: [Qemu-devel] [Bug 1334397] [NEW] cmos RTC alarms no longer wake system from suspend

[Paolo Bonzini <pbonzini@redhat.com>]

Il 25/06/2014 20:39, John Stultz ha scritto:
> Public bug reported:
>
> Running QEMU emulator version 2.0.0 (Debian 2.0.0+dfsg-2ubuntu1.1),
> booting Linux kernels with qemu-system-x86_64 and qemu-system-i386, I no
> longer see the system resume from suspend when an RTC alarm is set.
>
> My simple test application can be found here:
> https://github.com/johnstultz-work/timetests/blob/master/alarmtimer-suspend.c
>
> Previously this worked w/ QEMU 1.5  (bascially up until I upgraded from
> Ubuntu 13.10 to Ubuntu 14.04, which came with 2.0).

Ok, bisected.  The first commit to break it is:

     commit c046e8c4a26c902ca1b4f5bdf668a2da6bc75f54
     Author: Michael S. Tsirkin <mst@redhat.com>
     Date:   Wed Sep 11 13:33:31 2013 +0300

         piix4: disable io on reset

and the first commit to fix it is:

     commit db76ec6291df8a03c2cc82ea1249049383cca392
     Author: Gerd Hoffmann <kraxel@redhat.com>
     Date:   Thu May 15 14:01:59 2014 +0200

         seabios: update to 1.7.5-rc1

Yesterday I could not reproduce it because, even though Fedora has QEMU 
2.0.0, it has already updated SeaBIOS to 1.7.5.

In fact, the fix is actually not in QEMU but rather in SeaBIOS:

     commit 40d020f56226aee7c75a6c29f471c4b866765732
     Author: Marcel Apfelbaum <marcel.a@redhat.com>
     Date:   Wed Jan 15 14:20:06 2014 +0200

         resume: restore piix pm config registers after resume

Ubuntu can fix it by upgrading to SeaBIOS 1.7.5, or including this patch 
in their package (untested, but looks pretty safe).

Paolo