On Tue, Sep 18, 2012 at 01:19:31PM +0200, Robin Axelsson wrote:
With a pvops dom0 Xen resets devices by writing to its "reset" node in sysfs so it will reset the device using whatever method the dom0 kernel supports for that device.
And if you use Xen PCI-back it has this enabled so you don't even need the 'reset' functionality.
The version of Linux I have to hand has, in __pci_dev_reset, calls to the following in this order and stops after the first one which succeeds: * pci_dev_specific_reset (AKA per device quirks) * pcie_flr * pci_af_flr * pci_pm_reset * pci_parent_bus_reset
See drivers/pci/pci.c in the kernel for more info.
IIRC classic Xen kernels had similar code in pciback, although I don't know which specific sets of actions or in which order they were tried.
Ian.
That sounds like great news, that means that FLR is not a requirement to successfully pass through hardware without errors, as is stated in the VTdHowTo page. So it seems that the VTdHowTo page needs to be updated with this information.
Do you want to update the wiki page? :)
-- Pasi