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Re: [Qemu-devel] [PATCH] all vga: refuse hotplugging.
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH] all vga: refuse hotplugging. |
Date: |
Wed, 26 May 2010 12:49:08 +0100 |
User-agent: |
Alpine 2.00 (DEB 1167 2008-08-23) |
On Wed, 26 May 2010, Gerd Hoffmann wrote:
> On 05/26/10 12:59, Stefano Stabellini wrote:
> > On Wed, 26 May 2010, Gerd Hoffmann wrote:
> >> Try to pci hotplug a vga card, watch qemu die with hw_error().
> >> This patch fixes it.
> >>
> >
> > Do you know the reason why we get hw_error()?
>
> Because the card tries to register the legacy vga ports which are
> already taken by the primary card. I also don't know whenever you can
> pci hot-plug hardware which uses non-pci ressources at all.
>
> > Theoretically vga hotplug should be possible at least for secondary
> > graphic cards (even though I suspect most operating systems wouldn't
> > cope).
>
> Yes. Assuming the virtual hardware in question can actually act as
> secondary, i.e. is fully programmable without the legacy vga ports. The
> standard vga can't. The cirrus looks doable, at least you can access
> the vga ports using the mmio bar.
I see, good point.
I guess the right fix here would be to return -1 in the stdvga case but
continue in the cirrus case and avoid registering the vga ioports when
used as secondary adapter.
Re: [Qemu-devel] [PATCH] all vga: refuse hotplugging., Paul Brook, 2010/05/28