Looking to move on from udev - static /dev vs mdevd?

[svayar]

I've been recently seeing how much "fat" I can trim and so far it's been going alright - I yote pam and dbus without too much trouble, switched to a musl profile and figured how to run xorg elogind-less. One of the last obstacles is udev, but documentation is scarce, mostly in the form of the YeOldGentoo and mdev wiki pages. I don't mind the headaches that might come from attempting such a thing but I'm unsure which approach will make more sense or on my machine. I've read some forum posts here explaining their love for static /dev but I was likely too young to use a computer when that was a thing so I don't know much about it.

Anyway, my machine is a Dell G5 SE (laptop):

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Ryzen 7 4800H
Radeon Vega 7 (iGPU)
Radeon RX5600M (dGPU)
32GB DDR4 @ 2933MHz
A couple NVME drives
Intel AX200 (iwlwifi)

The dGPU has been a major headache in both Linux and Windows and it's a niche enough model that I'm not expecting improvements at this point so it's one of my main concerns, though I don't know how much this has to do with udev at all.
Networking seems also a bit more of an inconvinience without udev but I think I'll manage. I'd like to have functional bluetooth but given that bluez requires dbus, I've kinda given it up at this point.
My #1 concern is my drawing tablet - not too much info on this topic on linux in general but it seems like you need libinput, which relies on udev.

Any thoughts?

[NeddySeagoon]

svayar,

What is your tablet?

udev won't make any difference to your GPU. For networking, udev only changes one set of corner cases for another.
Your network interface names will revert to kernel names without udevs 'persistent' device names.

To practice that, add

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net.ifnames=0

to the kernel command line.
Wifi still works.

I've not tried bluetooth.

What drawing tablet do you have?

I can confirm that libinput has a hard (in the source code) dependency on libinput.

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Run-time dependency libudev found: NO (tried pkgconfig and cmake)

meson.build:146:0: ERROR: Dependency "libudev" not found, tried pkgconfig and cmake

I have a static /dev and no udev.

x11-drivers/xf86-input-wacom is still a thing but that won't build without udev either. it needs dev-libs/libwacom.

[svayar]

Gaomon S620 iirc. On Arch / Gentoo I've only managed to make it work with OpenTabletDriver but on my Ubuntu usb stick it tends to work ootb.

[colo-des]

My comment will surely not contribute much, but it is related to what you say about the defatting.

Many times I have wondered why are not allowed to create their own user profiles and that they are respected by emerge
but since I started reading things like (forced by profile) I stopped liking it, I update less and less and every
time my local tree is bigger and unmanageable due to eclass updates... all because of not allowing the user
make their own decisions on their own pcs.

In gentoo I have stayed with eudev and xorg-server in user mode, without pam, at-spi2, dbus, elogind, udev, *.kit, initramfs, xdm, display-manager...
I repeat it again the problem is emerge/portage with its profiles that take away the possibilities of choosing what you want and how.

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my-user@pc-gentoo ~ $ eix -Ic eudev
[I] sys-fs/eudev (3.2.5[1]@03/05/21): Linux dynamic and persistent device naming support (aka userspace devfs)
[1] "repo_local" /usr/local/portage

My new adventure is with LFS/BLFS using CRUX's pkgutils as binary package builder and manager, I've created the ports
(271 so far) using the LFS/BLFS guides and for packages that are not in the guides use the CRUX ports for reference
installed and updated by the CRUX ports package.

I comment this to get to show that in both LFS and CRUX, eudev is alive and kicking which I have installed and it works wonders.

Now I'm in gentoo, but chroot in BLFS, this is the data:

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my-user [ ~/adm ]$ pkginfo -i |grep eudev
eudev 3.2.11-1

my-user [ ~/adm ]$ pkginfo -i |grep sysvinit
sysvinit 3.05-1

my-user [ ~/adm ]$ revdep -v |head -n3
** calculating deps
** checking 271 ports
** checking linking

And these are the CRUX ports for uedev and sysvinit:

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my-user [ ~/adm ]$ prt-get info eudev
Name:         eudev
Path:         /usr/ports/core
Version:      3.2.11
Release:      1
Description:  Userspace device management daemon
URL:          https://github.com/eudev-project/eudev
Maintainer:   CRUX System Team, core-ports at crux dot nu
Dependencies: kmod

my-user [ ~/adm ]$ prt-get info sysvinit
Name:         sysvinit
Path:         /usr/ports/core
Version:      3.05
Release:      1
Description:  The Linux System V Init
URL:          https://savannah.nongnu.org/projects/sysvinit/
Maintainer:   CRUX System Team, core-ports at crux dot nu

In LFS you have the current guide at:
https://www.linuxfromscratch.org/lfs/vi ... eudev.html

I am very interested in experimenting and getting to use static devices...it is better to be prepared for what is coming.

Greetings

[NeddySeagoon]

colo-des,

Maybe linuxfromscratch needs a version bump.

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* app-doc/linuxfromscratch
     Available versions:  11.0 {htmlsingle pdf}
     Homepage:            http://www.linuxfromscratch.org/lfs
     Description:         LFS documents building a Linux system entirely from source

You can write your own profiles from scratch, if you want, portage can use them.
Its lot less work to modify an existing profile using /etc/portage/profile.
Its documented in

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man portage

If you are concerned about bloat and keeping things small, the gentoo:: repo is only about 80Mb in squashfs.
squashfs images of the repo have been available for a long time.

[NeddySeagoon]

svayar,

The Gaomon S620 is advertised for Windows and Apple.
The Linux Open TabletDriver looks like a wrapper around the windows driver, in much the same way as nvidia-drivers is a wrapper/shim around the windows nVidia driver and we used to have ndis-wrapper for win-modens.
You wont be able to fix that to not require udev.

If its a USB device, what does

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lsusb

say about your tablet?

[svayar]

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Bus 001 Device 005: ID 256c:006d GAOMON Gaomon Tablet

lmk if you need output with --verbose flag or anything else

After some sifting around, Digimend seems to support it indirectly and they have articles for using xf86-input-evdev and xf86-input-wacom, never used a setup like this but it seems like a step in the right direction.

[NeddySeagoon]

svayar,

I'm only after the Vendor and Device IDs, that's the 256c:006d bit. Its supposed to be unique to the device.
Putting

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linux usb 256c:006d

into your search engine of choice often turns up a driver, if there is one.

[svayar]

Indeed, the device ID matches a few tablets supported by digimend driver, which seems like it doesn't rely on libinput? not sure.

Overall, given my skill level, I think mdevd will probably be the better option for now. Other than your install guide on the wiki I haven't found any info on /static dev and I'm not sure how to apply it to converting an existing system but I'm undecided yet.

[colo-des]

neddyseagoon

Thanks for the tips on the profiles, I had searched a time ago and had not found anything relevant, but now I found lots of stuff to try.
I want to define my own set of packages for @system (one by one) with their uses and that emerge doesn't complain at all of my decisions
...in blfs with pkgutils nobody tells me anything, nobody opposes, they are all simple packages that at most they will give compilation
errors if their dependencies are not well resolved or patched to avoid them.

Greetings

[NeddySeagoon]

colo-des

The @system set starts with

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/var/db/repos/gentoo/profiles/base/packages

All profiles inherit that.
Now the bit that makes my head hurt ... profiles 'cascade'.
That is every step down the profile tree you go the new layer can add or remove things from the parent layer.

Its quite OK to make an overlay that contains its own profiles and do your own thing.

A word of caution, @system set packages are always assumed to be installed.
This means that
a) ebulds that depend on @system set packages only explicitly declare them if there is a good reason
e.g. a minimum gcc version
b) the dep tree for system set packages is usually not complete.

Those two things together means that portage cannot determine the correct build order for system set packages.

Its your Gentoo. When it breaks, you can keep all the pieces :)
Where would the fun be without that?

[colo-des]

I understand that the packages that are part of the build tools and the base system must be installed for it to work everything correctly,
what I don't agree is which tools and which versions.
The .ebuilds are created with rules that define minimum or maximum versions of their dependencies and even some artificially forced
(I have verified it) so it is that the creators of the .ebuilds are deciding for me what I should use and what I should have installed.
A broken gentoo doesn't work for me, but neither does a healthy one with those characteristics.

The cascading profiles, is the opposite of the KISS principle... too much desire to complique things, anyone understands the simple things,
the complex ones are not used and everyone goes to use the default ones without trying to touch anything because it is not understood or you are afraid to break.

Greetings

[stefan11111]

Don't know if this is what you need, but can't you set -* as the first useflag in make.conf and work from there, more or less ignoring profiles?

[stefan11111]

I yote pam and dbus without too much trouble

What browser do you use? I've been trying to remove dbus too, but librewolf depends on it even with USE="-dbus".

[NeddySeagoon]

colo-des,

The cascading profiles, is the opposite of the KISS principle... too much desire to complique things, anyone understands the simple things,
the complex ones are not used and everyone goes to use the default ones without trying to touch anything because it is not understood or you are afraid to break.

Like much of the PC, things have been just 'grafted on' over the years.
Intel tried a fresh start with their Itanic :) CPU but the rest of the world couldn't afford the extra work that forced.

As stefan11111 pointed out, you do not need to use profile USE flags.

You can also write your own profile from scratch. The cascading feature is provided by portage. There is no need to use it.
The ::gentoo profiles do bu feel free to collapse one closer to your liking and put it in your overlay.

I feel your pain with some of the ebuild choices made by the devs. I keep patching udev out in my overlay because I like a static /dev and no autoblackmagic at all.
My profile tweaks include (-udev) (-systemd).
Packages providing them are also masked. genkernel, dracut, elogind and others could be in the banned list but I won't gain anything. They are easy to avoid.

Feel free to keep your own overlay. Put it on github for safe keeping and to allow other like minded people to share and contribute to.

Gentoo is a toolkit. Use as much or as little of it as required to get your distro working your way.

[Hu]

Don't know if this is what you need, but can't you set -* as the first useflag in make.conf and work from there, more or less ignoring profiles?

Yes, this can be done. We even have at least one user who periodically posted support requests that were frequently traced to this choice, where we would find that some optional feature that almost everyone wants was disabled because of that USE=-*.

[stefan11111]

Don't know if this is what you need, but can't you set -* as the first useflag in make.conf and work from there, more or less ignoring profiles?

Yes, this can be done. We even have at least one user who periodically posted support requests that were frequently traced to this choice, where we would find that some optional feature that almost everyone wants was disabled because of that USE=-*.

My system has been running for quite some time with USE=-* as the first use flag in make.conf. Thanks to this, I have gone from over 750 packages to 670 packages and my system works fine. The only drawback is that my package.use has 100 lines in it because of this useflag.

[NeddySeagoon]

stefan11111,

We normally only hear from the people that get it wrong here :)
As you say, it can be made to work.

[colo-des]

@stefan11111

That idea of putting USE=-* did not occur to me, I have always disabled them individually, anyway my packages.use file
it's terribly big, especially due to multilib and multislot, years ago I've defined package by package what you use and what I don't.

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my-user@pc-gentoo ~ $ cat /etc/portage/package.use/package.use |wc -l
309

My compendium of disabled... there are archaic things that no longer exist for years, I see that it is better to USE=-* and focus on package.use

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USE=-accessibility -acl -arts -bluetooth -cdio -consolekit -curl -dbus -kde -gdm -gnome -hal -ldap -libav -libnotify -nautilus -networkmanager
-mono -aqua -plasma -qt3support -qt3 -qt4 -semantic-desktop -suid -systemd -snappy -tcmalloc -jit -python_targets_python2_7 -http2 -http3 -elogind
-polkit -policykit -pam -gvfs -webkit -libinput -clang

If you want to remove dbus from the browser you will have to copy the port to your local tree and edit the .ebuild then rebuild Manifest with the command

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ebuild <package.ebuild> manifest

@NeddySeagoon

My installation is 10 years old and over time I have seen how things have changed in gentoo, I use raid1 with mdadm and metadata-0.90
in order not to need initramfs and rely on having things like genkernel or dracut installed, metadata-0.90 is detected and used directly without
kernel problems without having to have initramfs, raid1 allows me to change the disks one by one and mirror itself automatically without restarting gentoo
from scratch... can say I've only installed gentoo twice in my life, once in march 2008 which ended with a dead disk in april 2012 and from there
until now I continue with the same installation I have even changed the motherboard that has been damaged by an electrical storm.

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my-user@pc-gentoo ~ $ genlop -t gentoo-sources |head -n3
  * sys-kernel/gentoo-sources
      Wed Apr 11 23:39:02 2012 >>> sys-kernel/gentoo-sources-3.3.1

Well, I'll try to create a profile without a parent to avoid the cascades, I've been reading a lot and it doesn't look complex, what does hurt is seeing
as in some .ebuilds, it is artificially forced to depend on packages that are not necessary and that are also a danger.

I have read about you and his profession, can say that we are colleagues...
https://blog.desdelinux.net/en/gentoo-t ... -the-myth/

I am an electronic technician, repairman and hardware developer, I have installed kicad and I want to update to kicad 7 but first I have to be able
to recreate everything since I haven't updated gentoo in almost a year.

Regards

[NeddySeagoon]

colo-des,

That page is out of date. I retired from the board of the Gentoo Foundation is 2016 since I retired from paid employment too and didn't know if my Gentoo time would be predictable.

You can update your install from any age, provided you can get the sources. The ebuilds are all in git.
It can be a challenge to do it all in one go from about a year or more but 6 month steps, approximately, will work.
I updated a 2011 install in 2019 and made a few notes too.

If you don't want to use git, there are squashfs repo snapshots too. To use them, your kernel needs squashfs support.

[Hu]

what does hurt is seeing
as in some .ebuilds, it is artificially forced to depend on packages that are not necessary and that are also a danger.

Could you elaborate on this? Inherently dangerous packages have no place in the main tree, and nothing should be depending on them. Similarly, if an ebuild has a dependency that is not needed, that is likely an oversight and should be reported.

[colo-des]

@Hu

What for some is a danger, for others is a gift from heaven and they want it... I consider dbus a danger and I see that they do the impossible
from many packages to put it as a dependency directly or indirectly.
I don't remember the cases right now since I haven't updated for almost a year or even look at my local tree, but I remember things like mupdf
forcing to install mujs although the use -javascritp had it disabled, I masked it and it stayed in that version for a long time until I eat
three versions later disabling -javascript really started to work.
libreoffice that runs out of menus if dbus is not active... I'm not going to blame gentoo for that, but the wolf's ears can be seen.
The good part of all this is that I had to learn how to edit .ebuilds, the bad part is that my local tree is unmaintainable, so
I'm trying to emigrate to BLFS... but I'll try to create my own profile and see how I organize myself to continue using it since I have three pcs
with gentoo and it's a shame to have to abandon it after so many years.

Regards

[svayar]

I yote pam and dbus without too much trouble

What browser do you use? I've been trying to remove dbus too, but librewolf depends on it even with USE="-dbus".

Firefox, so fairly similar. Itself, it won't pull dbus without the use flag but it pulls in gtk3, which in turn pulls in at-spi2-core, which pulls in dbus (I don't need any accessibility things on my PC, but gnome devs seem hellbent on removing features people use and making mandatory those that are seldom used...). Keep in mind that this is a method I came to with sifting through forum posts and pestering people on discord / irc, I've only used gentoo for 4-5 months so this is likely a suboptimal way to do it.

To start off with, you'll need an overlay that ships a patched gtk package (either mv or pg_overlay). Now you'll be able to emerge gtk without pulling in at-spi2-core as a dependency, *but* if you don't have it installed the build will fail still.
Personally, I added

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app-accessibility/at-spi2-core-2.46.0

to

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/etc/portage/profile/package.provided

this should shut up about firefox itself pulling it in as a dep. In order to be able to build gtk+ you will need to emerge

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=dev-libs/atk-2.38.0

and preferably mask later versions as world updates might become a sticky situation.

Again, not a pretty solution, but until someone smarter posts something less hacky, it will work. :D

[stefan11111]

I yote pam and dbus without too much trouble

What browser do you use? I've been trying to remove dbus too, but librewolf depends on it even with USE="-dbus".

Firefox, so fairly similar. Itself, it won't pull dbus without the use flag but it pulls in gtk3, which in turn pulls in at-spi2-core, which pulls in dbus (I don't need any accessibility things on my PC, but gnome devs seem hellbent on removing features people use and making mandatory those that are seldom used...). Keep in mind that this is a method I came to with sifting through forum posts and pestering people on discord / irc, I've only used gentoo for 4-5 months so this is likely a suboptimal way to do it.

To start off with, you'll need an overlay that ships a patched gtk package (either mv or pg_overlay). Now you'll be able to emerge gtk without pulling in at-spi2-core as a dependency, *but* if you don't have it installed the build will fail still.
Personally, I added

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app-accessibility/at-spi2-core-2.46.0

to

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/etc/portage/profile/package.provided

this should shut up about firefox itself pulling it in as a dep. In order to be able to build gtk+ you will need to emerge

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=dev-libs/atk-2.38.0

and preferably mask later versions as world updates might become a sticky situation.

Again, not a pretty solution, but until someone smarter posts something less hacky, it will work.

Thanks, that worked. Was this reported to the librewolf devs?

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Calculating dependencies... done!
>>> Calculating removal order...

>>> These are the packages that would be unmerged:

 sys-apps/dbus
    selected: 1.15.4
   protected: none
     omitted: none

 acct-user/messagebus
    selected: 0-r1
   protected: none
     omitted: none

 app-text/docbook-xml-dtd
    selected: 4.4-r3
   protected: none
     omitted: 4.1.2-r7 4.2-r3 4.3-r2 4.5-r2

 acct-group/messagebus
    selected: 0-r1
   protected: none
     omitted: none

Somewhat concerned about these hacks, but my system is full of them.

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$ cat /etc/portage/package.mask
# use libressl
dev-libs/libevent::gentoo
dev-lang/python::gentoo
dev-lang/ruby::gentoo
dev-lang/rust::gentoo
dev-perl/Net-SSLeay::gentoo
dev-libs/openssl::gentoo
# go back to a static /dev
sys-fs/eudev
sys-fs/udev
sys-auth/polkit
sys-auth/consolekit
media-sound/pulseaudio
sys-apps/systemd
# librewolf without dbus
>dev-libs/atk-2.38.0

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$ cat /etc/portage/profile/package.provided
app-accessibility/at-spi2-core-2.46.0
net-libs/glib-networking-0.4.18
x11-base/xorg-drivers-21.1-r2
virtual/tmpfiles-0-r3
sys-fs/udev-init-scripts-35

What did you do about your /dev?
I use a static /dev, but for some reason steam wants udev to be installed(not running, just installed).
Also curious about how you removed pam. I did it too, but ended up writing my own su as util-linux with USE=su also forces USE=pam.

[Leonardo.b]

An alternative is "su" from suckless.org utils.
There is no Gentoo package for it.