Re: [OE-core][PATCH] rng-tools: Change "Requires" to "WantedBy" for dev-hwrng.device

[Khem Raj <raj.khem@gmail.com>]

On Fri, Aug 19, 2022 at 8:22 AM Alexander Kanavin
<alex.kanavin@gmail.com> wrote:
>
> So which recent patch? Can you link to it please?
>

https://patchwork.yoctoproject.org/project/oe-core/patch/20220813170156.4040589-1-raj.khem@gmail.com/

but this needs to remove sysinit from target, I have meant to send a
v2 but had no time to do so far.

> Alex
>
>
> On Fri, 19 Aug 2022 at 17:13, Drew Moseley <drew.moseley@gmail.com> wrote:
> >
> >
> > On 8/19/22 11:07 AM, Dragos-Marian Panait wrote:
> >
> >
> > On 19.08.2022 17:34, Drew Moseley wrote:
> >
> > [Please note: This e-mail is from an EXTERNAL e-mail address]
> >
> >
> > On 8/19/22 8:50 AM, Dragos-Marian Panait wrote:
> >
> > Hi Claudius,
> >
> > On 19.08.2022 12:36, Claudius Heine wrote:
> >
> > [Please note: This e-mail is from an EXTERNAL e-mail address]
> >
> > Hi Dew.
> >
> > On 2022-08-15 20:25, drew.moseley@gmail.com wrote:
> >
> > From: Drew Moseley <drew@moseleynet.net>
> >
> > The previous change to remove the dependency on systemd-udev-settle
> > caused boot delays at least on qemu. It seems that change required
> > a hwrng device but that's not necessarily available on all platforms.
> >
> > This changes the "Requires" to a "WantedBy" as modeled after the
> > version of this file on Ubuntu 20.04.
> >
> > Signed-off-by: Drew Moseley <drew@moseleynet.net>
> > ---
> >   meta/recipes-support/rng-tools/rng-tools/rng-tools.service | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/meta/recipes-support/rng-tools/rng-tools/rng-tools.service b/meta/recipes-support/rng-tools/rng-tools/rng-tools.service
> > index 0f50890dcb..b013d95932 100644
> > --- a/meta/recipes-support/rng-tools/rng-tools/rng-tools.service
> > +++ b/meta/recipes-support/rng-tools/rng-tools/rng-tools.service
> > @@ -3,8 +3,6 @@ Description=Hardware RNG Entropy Gatherer Daemon
> >   DefaultDependencies=no
> >   After=systemd-udev-settle.service
> >   Before=sysinit.target shutdown.target
> > -Requires=dev-hwrng.device
> > -After=dev-hwrng.device
> >   Conflicts=shutdown.target
> >
> >   [Service]
> > @@ -32,3 +30,4 @@ SystemCallFilter=@system-service
> >
> >   [Install]
> >   WantedBy=sysinit.target
> > +WantedBy=dev-hwrng.device
> >
> >
> > This looses the order. Have you tried just replacing `Requires` with
> > `Wants`. So something like this:
> >
> >
> > ```
> >
> > Before=sysinit.target shutdown.target
> > Wants=dev-hwrng.device
> > After=dev-hwrng.device
> > Conflicts=shutdown.target
> >
> > ```
> >
> > If that still would cause the long waiting time on qemu?
> >
> > I haven't investigated the qemu issue, but maybe qemu just doesn't
> > provide a hardware random source? If it doesn't provide a hardware
> > random source, then installing rng-tools on there might also not make sense.
> > Alternatively maybe just adding a start timeout might solve it?
> > regards,
> > Claudius
> >
> >
> > I've tested the patch on a NUC7, results are the same as with qemu:
> > - increased boot time
> > - timeout for rng-tools.service
> > [ TIME ] Timed out waiting for device /dev/hwrng.
> > [DEPEND] Dependency failed for Hard…e RNG Entropy Gatherer Daemon.
> >
> > Regards,
> > Dragos
> >
> >
> > Interesting. I guess this patch should definitely be ignored and the patch from Khem that removes both the dev-hwrng and systemd-udev-settle depencies is the right approach. That means that the original problem that adding systemd-udev-settle was meant to solve, is no longer solved but it seems that the proposed solutions here have adverse effects elsewhere.
> >
> > Simply removing the systemd-udev-settle dependency fixes the issue that my customer has that caused me to start investigating here.
> >
> > Drew
> >
> > --
> > mailto:drew@moseleynet.net
> >
> > Sorry for the confusion, I did not test any additional patches/changes that have been suggested in this email thread.
> > My test was performed on current Yocto master sources. No additional patches.
> > I just wanted to inform that the boot delay is also observed on real hw, not just qemu.
> > Again, sorry for the confusion.
> >
> > Dragos
> >
> >
> > Sorry for adding to the confusion. My point was intended to be that I am fairly certain the recent patch submitted by Khem will resolve the boot delay issue you are having as well as the original boot delay caused by systemd-udev-settle.
> >
> > Drew
> >
> > --
> > mailto:drew@moseleynet.net
> >
> >
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