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Re: [Qemu-devel] a user here - pci-assign


From: Alex Williamson
Subject: Re: [Qemu-devel] a user here - pci-assign
Date: Mon, 01 Oct 2012 07:51:34 -0600

On Mon, 2012-10-01 at 12:10 +0100, lejeczek wrote:
> hmm, still cannot get readon 5450 to work on win7-64, have 
> changed -cpu to host but no fix
> no vfio in qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64
> yes, I do blacklist modules at grub level and later in 
> modprobe also

You probably want to try newer upstream code.  RHEL does not currently
support assignment of VGA.

> is primary/secondary VGA setup somehow helped by 
> qemu/components? in guest I can do anything since device is 
> disabled.
> 
> pci-assign.multifunction=on/off - that would be the case 
> with VGAs like radeon and nvidia - audio part - is it 
> optional or always has to be ON for such devices?

Optional

> where one gets hold of information like: addr= ?
> I understand these are needed only! if pci-assign.host is 
> not enough and qemu has no way of knowing/finding it, when 
> may this happen?

This is not going to help you.  It's a matter of finding a free slot,
which qemu can do fine on it's own if you don't want to specify.
Thanks,

Alex

> On 28/09/12 20:48, Alex Williamson wrote:
> > On Fri, 2012-09-28 at 19:46 +0100, lejeczek wrote:
> >> thanks Alex for your patience, appreciate it I do
> >>
> >> what would be the droids I need?
> >> I'm experiencing guests' "puzzling" behavior and was
> >> suggested that command line arguments were wrong/incomplete.
> >>
> >> same box/hardware and radeon 5450 and ...
> >> - winXP-32bit -> OK - I assumed getting the guest on a
> >> external computer monitor was an ultimate test
> >> - win7-64bit -> OS reports device as disabled cause the
> >> device reported an error
> > I've had this same card working with both of these guests.  I believe
> > one trick on win7 was to use -cpu host.  Also, don't try to disable the
> > emulated vga device, just set it up like a dual-head system.  Once you
> > load the catalyst driver windows will switch to use the assigned device
> > exclusively.  I was using the new vfio assignment driver, but someone
> > else recently report it working with the existing driver as well.  The
> > 5450 should be a secondary graphics card on the host system, trying to
> > assign the primary graphics is going to cause more problems.  Also
> > blacklist the radeon driver on the host, we don't need any leftover
> > state from the Linux driver causing problems since most of these
> > graphics cards don't support a reset mechanism.
> >
> >> same box as above and geforce gt640 and ..
> >> for both XP and 7 report device with exclamation marks (thus
> >> did not even bother to connect any screens like in working
> >> case with XP & radeon)
> > I don't think we've seen any reports yet of Nvidia cards working,
> > there's another thread on the kvm list speculating at some of the
> > problems.
> >
> >> I'll try to get hold of ROMs of the cards, meanwhile, how
> >> can I troubleshoot it? how to get more verbose feedback and
> >> what to specifically look for?
> > ROMs are only going to help if you're getting errors trying to read the
> > ROM.  Nvidia seems to have this problem, but I don't think radeons
> > typical do.  There's a #define in the code that can be enabled to get
> > more logging, but it's not terribly useful unless you know what you're
> > looking at.  VGA has plenty of issues with legacy PC address ranges that
> > are known problems, but there are also plenty of unknown problems that
> > make it a pretty difficult black box debugging project.  Thanks,
> >
> > Alex
> >
> >
> >
> 
> 






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