[systemd-devel] Utility for persistent alternative driver binding

[Panu Matilainen]

On 12/06/2015 08:56 AM, Andrei Borzenkov wrote:
> 04.12.2015 12:40, Panu Matilainen пишет:
>> Hi all,
>>
>> To follow-up on this thread from September-October:
>> http://lists.freedesktop.org/archives/systemd-devel/2015-September/034427.html
>>
>> http://lists.freedesktop.org/archives/systemd-devel/2015-October/034551.html
>>
>>
>> The driverctl utility has matured a bit from the earliest tyre-kicking
>> version seen there and now lives at laiskiainen.org/git/?p=driverctl.git
>>
>> Since it has everything to do with udev this seems like a reasonable
>> forum to advertise it a bit. Quoting from the README a bit:
>>
>>> driverctl is a tool for manipulating and inspecting the system
>>> device driver choices.
>>>
>>> Devices are normally assigned to their sole designated kernel driver
>>> by default. However in some situations it may be desireable to
>>> override that default, for example to try an older driver to
>>> work around a regression in a driver or to try an experimental
>>> alternative
>>> driver. Another common use-case is pass-through drivers and driver
>>> stubs to allow userspace to drive the device, such as in case of
>>> virtualization.
>>>
>>> driverctl integrates with udev to support overriding
>>> driver selection for both cold- and hotplugged devices from the
>>> moment of discovery, but can also change already assigned drivers,
>>> assuming they are not in use by the system. The driver overrides
>>> created by driverctl are persistent across system reboots
>>> by default.
>>>
>>> Usage
>>> -----
>>>
>>> Find devices currently driven by ixgbe driver:
>>>
>>> # driverctl -v list-devices | grep ixgbe
>>> 0000:01:00.0 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>>> 0000:01:00.1 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>>>
>>> Change them to use the vfio-pci driver:
>>> # driverctl set-override 0000:01:00.0 vfio-pci
>>> # driverctl set-override 0000:01:00.1 vfio-pci
>>>
>>> Find devices with driver overrides:
>>> # driverctl -v list-devices|grep \\*
>>> 0000:01:00.0 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>>> 0000:01:00.1 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>>>
>>> Remove the override from slot 0000:01:00.1:
>>> # driverctl unset-override 0000:01:00.1
>>
>
> As was mentioned recently PCI bus numbers may change between reboots, so

Hmm, got a pointer? I dont think PCI slots change between reboots 
without physically swapping hardware, the "ethX-problem" comes from the 
order of device discovery being unstable across boots, which is a 
different issue and not relevant for this case.

> you may want to start with something more stable from the very beginning.

Such as? I dont see any other data that is there for all PCI (and USB) 
devices that allows differentiating between two otherwise identical devices.

	- Panu -