Re: [Xen-devel] Re: XEN boot hangs at ACPI: PCI Root Bridge [PCI0] (0000:00)

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Friday, November 12, 2010, 11:19:53 PM, you wrote:

> On Thu, Nov 11, 2010 at 09:16:35AM -0800, Neobiker wrote:
>> 
>> Hi Konrad,
>> 
>> many folks need to use the Xenlinux Kernel due to missing features in pvops
>> kernel...
>> For me (neobiker), it's at a minimum pvusb for my VDR System which uses an
>> usb device for DVB-S :-)

> You could also do PCI passthrough of your USB card to the domain..

I'm doing that, and it works, but there are a few pitfalls:
    - With onboard controllers it can sometimes be hard to tell which usb port 
ends up connected to which usb controller. Some motherboards seem to connect 
them up rather randomly,so you never know which one to passthrough, but it can 
differ per motherboard.
    - You don't have that problem when you passthrough a dedicated pci / pci-e 
controller card per domain.
    - With xhci (usb3) controllers you will most probably encounter problems, 
it hasn't matured enough yet (i'm back to usb2 again after trying for quite 
some time.)
    - Found some real cool usb2 controllers with a moschip 9990 chip, these 
pci-e cards have 4 usb ports, but the bonus is, it has 4 seperate usb 
controllers.
      That means every port has the full 480Mbps bandwidth, instead of having 
it shared for all port.Without that you can have only one video device per 
controller card, because that already saturates more than half the bandwidth 
most of the time.
    - All usb2 controllers i have had seems to work fine when passed through 
even without a hardware iommu.

So apart from these pitfalls it now seems to work like a charm !
Another possibility could be usbip which is in the staging tree of the linux 
kernel.

--

Sander

>> I also use a usb printer on my printer DomU.
>> 
>> Also, i think it is interesting, why the kernel doesn't work at this point,
>> the xen 4.0.2-rc1-pre version starts nowadays on this host - very strange
>> behaviour.

> That might be due to the fact that the drivers (2.6.`8.8) aren't up-to-date
> on your new box. You can also find out more details if pass in the Xen 
> hypervisor
> command line "sync_console console_to_ring " and in the Linux command line:
> "loglevel=8 debug initcall_debug"

> That should show you why and exactly where it fails in the bootup. The thing
> you are seeing isn't actually the failure, it occurs later on but the output
> is buffered and it never reaches Xen hypervisor unless you use those command 
> line
> arguments I mentioned.





-- 
Best regards,
 Sander                            mailto:linux@xxxxxxxxxxxxxx


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