[vbox-dev] Windows 10 guest additions video driver problem

[Anna Fischer]

> Betreff: Re: [vbox-dev] Windows 10 guest additions video driver problem
> 
> Hi,
> 
> On Monday 04 January 2016 17:21:33 Anna Fischer wrote:
> > > Betreff: Re: [vbox-dev] Windows 10 guest additions video driver
> > > problem On Tuesday 29 December 2015 12:54:01 Anna Fischer wrote:
> > > > I run Virtualbox 5.0.10 on Gentoo Linux. I run different guest
> > > > operating systems, one of them Windows 10 64-bit. All my guests
> > > > have
> > > > 5.0.10 guest additions installed. All guests work fine except the
> > > > Windows 10 guest: when I suspend the system (e.g. the host OS goes
> > > > into hibernation / suspend to RAM mode) while the VM is running,
> > > > and then resume the system, it seems as if the guest graphics
> > > > driver crashes. Initially when the VM comes back on the screen
> > > > after resume, it seems as if the resolution is switched to a lower
> > > > resolution, and then I get a message in the guest saying video
> > > > driver crashed. Has anyone else ever seen this? I only seem to
> > > > have the problem with Windows 10 as guest. All other guests still
> > > > work after resume, and their
> > >
> > > resolution does not change.
> > >
> > > do you see the same problem if you suspend + resume the VM? I'm
> > > asking because basically this is the same what happens when you
> > > hibernate or suspend your host: All VMs are suspended before the
> > > host suspends and all VMs which were suspended before are resumed
> after the host resumed.
> >
> > No, I don't see the same behavior, and I was expecting that it is a
> > different mechanism. Does VBOX actually detect that the host is trying
> > to hibernate, and then it will suspend all the VMs automatically? Is
> > that really how it works?
> 
> yes, at least if dbus works as expected, see here:
> 
> https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-
> server/linux/HostPowerLinux.cpp#L134
> 
> and here:
> 
> https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-
> server/HostPower.cpp#L74
> 
> and later we will arrive Main/src/client/ConsoleImpl.cpp line 6195.
> 
> The VBox.log file of running VMs should indicate if they are suspended/
> resumed on host suspend/resume.

To me the code looks as if the VM is actually paused, not suspended (e.g. saved). Is that so?

It does not make sense to actually really suspend a VM (e.g. save state), because for Windows 10 with 4-8 GB of RAM, this will take up to 30 seconds! During that time, my Linux is already suspended. It does not wait for VBOX to store any VMs.

 
> > To me it looks like the host is just putting everything that currently
> > runs to sleep, and then stores the RAM state on the SWAP partition.
> 
> Only if the dbus mechanism doesn't work. There is a different mechanism
> which works in host R0, see here:
> 
> https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Sup
> port/linux/SUPDrv-linux.c#L604
> 
> The corresponding callback is registered here:
> 
> https://www.virtualbox.org/browser/vbox/trunk/src/VBox/VMM/VMMR0/
> HMR0.cpp#L707
> 
> This second mechanism is used to disable VT-x/AMD-V during host suspend
> because many BIOSes are broken and don't handle this case properly.
> 
> > When I simply save and resume VMs (I do that all the time, btw.) it
> > works perfectly fine.
> 
> In that case please check the VBox.log file is the VM is really suspended/
> resumed during host suspend/resume. The VM should properly work after
> host suspend/resume even if the first (dbus) mechanism doesn't work but it
> makes sense to check if repairing it (if it doesn't work) makes a difference.
> 
> dbus is loaded on demand to VBoxSVC, if libdbus-1.so.3 is not there then
> VBoxSVC.log will contain the line
> 
>   HostPowerServiceLinux: DBus library not found.  Service not available.

I use DBUS for many of my own services, so it does run properly. 

I'm still wondering if this is a Guest Additions bug in Windows 10...
I'm also wondering if this ticket https://www.virtualbox.org/ticket/14409 is the same as what I see, just under Linux. When I pause the VM manually, I do not see the same effect. So there must be something is going on when suspending the host.

Regards,
Anna