Re: [Qemu-devel] [PATCH] hw/vmmouse.c: Disable vmmouse after reboot

[Gerhard Wiesinger <lists@wiesinger.com>]

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On Thu, 26 Jan 2012, Andreas Färber wrote:

> Am 25.01.2012 21:04, schrieb Gerhard Wiesinger:
>> Bugfix after reboot when vmmouse was enabled and another OS which uses
>> e.g. PS/2
>> mouse.
>>
>> Details:
>> When a guest activated the vmmouse followed by a reboot the vmmouse was
>> still
>> enabled and the PS/2 mouse was therefore unsusable. When another guest
>> is then
>> booted without vmmouse support (e.g. PS/2 mouse) the mouse is not working.
>>
>> Reason is that VMMouse has priority and disables all other mouse entities
>> and therefore must be disabled on reset.
>>
>> Testscenario:
>> 1.) Boot e.g. OS with VMMouse support (e.g. Windows with VMMouse tools)
>> 2.) reboot
>> 3.) Boot e.g. OS without VMMouse support (e.g. DOS) => PS/2 mouse
>> doesn't work
>>     any more. Fixes that issue.
>>
>> Testscenario 2 by Jan Kiszka <jan.kiszka@siemens.com>:
>> Confirm that this patch fixes a real issue. Setup: qemu.git,
>> opensuse 11.4 guest, SDL graphic, system_reset while guest is using the
>> vmmouse. Without the patch, the vmmouse become unusable after the
>> reboot. Also, the mouse stays in absolute mode even before X starts again.
>>
>> Fixed by:
>> Disabling the vmmouse in its reset handler.
>>
>> Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
>
> I've been able to reproduce this the day before yesterday, on my version
> of qemu-kvm 0.15.1 with this patch apparently fixing the mouse after a
> kdump.
>
> Yesterday however the reporter applied the patch himself to qemu.git and
> reported this patch not to fix it on their side.
>
> We boot into the desktop, then do:
> # echo 1 > /proc/sys/kernel/sysrq
> # echo c > /proc/sysrq-trigger
> System then reboots after a while and at login mouse does or does not work.
>
> I had originally tried to kdump with just a virtio drive w/ default
> settings; then I tried with the reporter's setting of -smp 4 (and
> cache=unsafe) and was able to reproduce it. Afterwards I was able to
> reproduce without -smp 4 as well; no recompilation occurred. Guest was
> the same SLES11 SP2 RC2 all the time.
>
> So, is there any indeterminism involved? I.e. is the mouse unusability
> maybe not 100% reproducible? Anything else that may need to be fixed
> beyond this patch?
>
> Patch does not break anything, so for now:
>
> Tested-by: Andreas Färber <afaerber@suse.de>

All known issues I detected were fixed with the patch for me reproducable 
at least for now.

Ciao,
Gerhard

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