RE: [Xen-devel] Re: [PATCH 0/2] passthrough: make management of PCI D-states by guest optional

[Kouya Shimura <kouya@xxxxxxxxxxxxxx>]

Cui, Dexuan writes:
> Yuji Shimada wrote:
> > On Fri, 6 Mar 2009 14:23:20 +0900
> > Kouya Shimura <kouya@xxxxxxxxxxxxxx> wrote:
> > >
> >> Using D3hot state of PCI devices in xen is not mature yet.
> >> I met domain destruction/creation troubles in some PCI cards since
> >> the PCI config registers can't be read with D3hot state. xend.log is
> >> attached. 
> >>
> >> This patch set makes the management of PCI D-states by guest optional.
> >> 
> >> The default is "pci_power_mgmt=0" which disables the guest OS from
> >> managing D-states because it would be better to avoid the trouble than
> >> advantage of low power consumption.
> Is this the only reason to add the guest config parameter?
> If yes, I don't think it is worthwhile to have two over-200-lines patches.

If the answer was yes, I would have proposed to revert the patches
about PCI D-states. This patch enables individual setting for each PCI
passthru device and that requires many lines.

Supposing a PCI device has a hardware bug, that is possible, don't you
wish to disable *only* it?  Actually, Q-logic FC card which has two
PCI functions looks ill.

Any way, tool part of this patch is committed.

> IMO we should fix the code in xend.

I hope so, too.  After that, turn on "pci_power_mgmt=1".

Thanks,
Kouya

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel