On 08/26/2016 10:32 PM, Daniel Reurich wrote:
> On 27/08/16 12:05, Ralph Ronnquist wrote:
>> Hendrik Boom wrote on 27/08/16 08:52:
>>> On Sat, Aug 27, 2016 at 08:45:35AM +1000, Ralph Ronnquist wrote:
>>>> ..
>>>> 3) Off hand I would say it would work, but on the other hand, afaik
>>>> vdev is
>>>> still in beta state. And I don't know anything about rpi3. To try it
>>>> out,
>>>> you should first make sure you can revert easily. But I haven't
>>>> thought too
>>>> much about how to do that. In practice, vdev conflicts with udev,
>>>> libudev1
>>>> and initramfs-tools, because it removes or overwrites files (/links)
>>>> from
>>>> these.
>>>
>>> It would be convenient from a user perspective, especially while we
>>> are still testing, to be able to choose udev or vdev at boot time,
>>> perhaps as a kernel parameter. But if the packages conflict to this
>>> degree, I suppose there isn't much hope of it.
>>
>> Agreed about convenience. Though without thinking too deep about it,
>> it'd mean improving(?) both initramfs-tools and sysvinit (and
>> alternatives) towards maintaining concurrent alternative initrd, and
>> startup choice respectively. I'm sure it _could_ be patched into the
>> vdev installation to provide a dynamic choice between it and a prior
>> udev (for some systems), but I think it'd violate the package
>> independence thought quite severely; much worse than it already does.
>>
>> In the present incarnation, the rollback (not tested by me, though) from
>> vdev to udev is (should be): remove vdev and libudev1-compat (and
>> perhaps vdevd), then reinstall udev, libudev1, and initramfs-tools.
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>
> I'd imagine it should be possible to include both udev and vdev in the
> initrd and add a boot option to select which device manager to use.
>
> Once I've I've got a moment I'm going to jump in on this and see if we
> can get a vdev package into experimental and work towards including it
> in jessie-backports.
>
>


What I've been doing to switch between vdev and udev is to edit the boot
command at the grub menu.

Save a copy of the pre-vdev initrd under a different name.
To boot with udev, edit the boot menu to point to this intird, and add
init=/bin/bash to the linux line.

At the intiramfs prompt:

/etc/init.d/udev start
exec /sbin/init

vdev will start anyway, but you can stop it when it's done. If you remove
the symlink under rcS.d then it won't start automatically.

If you want to get fancy, make two scripts, /sbin/init-vdev and
/sbin/init-udev, containing the two commands I listed above (change udev
to vdev for the vdev script.)

Make two boot entries, one points to the vdev initrd and has
init=/sbin/init-vdev on the linux line and the other points to the udev
initrd and has init=/sbin/init-udev on the linux line.

Sadly, I'm not getting Ralph's i386 build to boot. It's hanging on usb
(keyboard). Any time I type, I get a usb disconnect and connect message.

-fsr