On 10/13/2015 03:24 PM, Harald Hoyer wrote:
On 13.10.2015 14:08, Panu Matilainen wrote:
On 09/30/2015 08:43 PM, Flavio Leitner wrote:
On Tue, Sep 29, 2015 at 12:30:54AM +0300, Mantas Mikulėnas wrote:
I wonder if this could be handled with a generic Type=oneshot,
ExecStart=driverctl bind foo...
Could you elaborate more on that?
If driverctl is an utility, we could use scripts, yeah. The issue
is how to identify the device. We probably would need some sort
matching mechanism like udev does.
Since the silence is deafening, and since its usually easier to poke holes in
something concrete no matter how incomplete and/or broken, here's a beginning
of an approach to alternative driver assignment in the udev realm:
http://laiskiainen.org/udev/driverctl/
# <copy/patch the bits to their places>
# echo vfio-pci > /etc/driverctl.d/0000:01:00.0
# echo 1 > /sys/bus/pci/devices/0000:01:00.0/remove
# echo 1 > /sys/bus/pci/rescan
...and there you go, udev vfio-pci is forced for that device on the rescan, and
a real hotplug is handled similarly.
Since normally the device probing occurs early in the boot, these things also
need to go to initramfs so a dracut module/patch is needed, and dracut needs to
be run after adding devices here, ie
# echo vfio-pci > /etc/driverctl.d/0000:01:00.0
# dracut -f
# reboot
Having to mess with initramfs is a bit of a PITA but at least some of that
could be hidden in the driverctl utility, and then overriding the default
driver early in the boot means we get none of the side-effects with interfaces
coming and going, possibly wrestling with NetworkManager over it etc.
For a real-world implementation there are tons of TODOs like
- support non-pci buses
- support direct bind/unbind in driverctl
- million errors situations to check
- vfio & uio -bound devices disappear from systemd, we'd probably want them
there in some form to be able to depend on them
- etc...
- Panu -
I don't know nothing about driver binding/unbinding,
Neither do I, that's why I'm asking here ;)
but what happens if the
initial driver binding (with the wrong driver) happens in-between these lines?
if [ -L /sys/$DEVPATH/driver ]; then
echo "$DEV" > /sys/$DEVPATH/driver/unbind
fi
[…]
--->> HERE the other driver binds to the device <<<----
[…]
echo "$DRV" > /sys/$DEVPATH/driver_override
The wrong thing probably... The unbind probably doesn't belong there at
all, I added it there for the wrong reason and forgot to remove.
Thanks for pointing that out though.
- Panu -
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