Got udev working, now what?!

nepenthe · Guru Joined: 14 Jul 2002 Posts: 317 Location: Sanford, ME

sweet
=)

nepenthe · Guru Joined: 14 Jul 2002 Posts: 317 Location: Sanford, ME

Here is latest i see...

http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev-015.tar.gz

=)
nep

Superduck · Posted: Tue Jan 27, 2004 4:48 am Post subject:

The new udev changes quite some things, I've reported a bug on bugzilla for this new version:

https://bugs.gentoo.org/show_bug.cgi?id=39517

udev has solved all the problems I had with usb disconnect / connect of storage devices. I'm looking forward to setting my comp up so that when I plug in my usb flash it will ask me for my password (encrypted fileystem on it, where I store stuff like private ssh/gpg keys)

charlieg · Posted: Tue Jan 27, 2004 7:03 am Post subject:

The combination of udev, hotplug, DBUS, HAL... once all this gets polished the Free Software desktop will be doing things the right way and really will show it's quality.
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uglyman · Posted: Thu Jan 29, 2004 1:34 am Post subject:

hi all,
this thread helped me get up and running last week with midi on my emu10k1. I have come here first cause I figure that you guys have systems that are very close to mine (udev, 2.6 kernels, etc). So I had my sound stuff working perfect. Even midi was working fine. Then I had moved on to messing with lirc, the next thing on my todo list. I have been keeping up to date with the latest packages of everything in hopes of turning up some bugs (I am unemployed and bored).

I noticed my dvd playback was really ugly. I realized dma was off and I couldn't turn it on. So I noticed I had forgotten to compile support for my ide chipset ( :oops:

). I did make menuconfig and added it and then built/installed and restarted. The good news is that I can now turn on dma to my dvd drives. The bad news is that alsa broke, badly. :cry:

As alsa tried to start (due to the rc script alsasound in boot runlevel) it all seems to be working until it gets to the seq/oss emu related modules and then it gives tons of unresolved symbols messages. I find this very odd considering I didn't think I changed anything even remotely related to alsa. This was with my 2.6.2-rc1 kernel. I tried all kinds of stuff as far as re building and re-installing the kernel and its modules. Then I tried the older 2.6.1 kernel I had laying around. That had the same errors.

I thought maybe I had run across something that was already fixed so I did emerge sync and emerge -pUD world. It turned up alsa-libs and alsa-utils. So I thought maybe emerging those and then redoing the kernel stuff would get me going again. When I tried to emerge alsa-libs it gave an error I had never seen before about how the digest didn't match up. I deleted what I had in the distfiles dir (the tbz2) and tried again. this time it worked. So I set about trying the same things in the kernel config/build/install arena but with no luck. I still get unresolved symbols on everything related to oss emu. Is anyone else seeing this, or can anyone give me a hint? I am really out of ideas!

thanks!
ugl

uglyman · Posted: Thu Jan 29, 2004 6:48 am Post subject:

ok I made some progress.

I recompiled with alsa stuff builtin and (magically) lirc started working with my SBlive drive rm-900. First time I have ever had that working since I bought it years ago! The problem is that now my original problem with /dev/sequencer is back.

I am starting to get frustrated, but I guess this is the price you pay, if you want to live in the general neighborhood of the bleeding edge. I created my alsa devices with the snddevices script in the alsa-driver package. is there something I can use in /dev/snd as a sequencer?

This is my latest theory: Can't get alsa working as modules lately... possibly related to my tinkering with lirc somehow (or I suppose, my ide chipset, but I doubt that). I get unresolved symbols if anything related to alsa is a module. Alsa works builtin without a problem, with the exception that I get errors when trying to access /dev/sequencer. My theory is that udev can't help with /dev/sequencer if alsa stuff is not modules. This gives me a nasty chicken vs egg kind of thing. Can anyone suggest a workaround? or can I somehow configure udev differently? Is there a command that would make a static /dev entry that would fix this?

thanks for the help
uglyman

Trejkaz · Posted: Fri Jan 30, 2004 12:37 am Post subject:

Just something I noticed, that udev population script will populate the audio devices such that an ordinary user in the audio group can't use the mixer, and possibly can't play sound but I'm not at the computer to be able to see. :-)

Is there something I'm missing or shouldn't all the audio devices be mode 660?

Also, I made nvidia-ctl 660, group 'users'... which feels a little safer. Though to be stricter I probably should exclude users who I only give a remote login...

Evil Dark Archon · Posted: Fri Jan 30, 2004 4:27 am Post subject:

my experience with udev is mostly uneventful, except for a huge speedup, even bigger with udev 015, the only issue i have is that i have to either have alsa compiled into the kernel (which i will not do) or have the modules load before the alsasound init script in order for the alsasound initscript to restore the mixer levels correctly.
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nepenthe · Guru Joined: 14 Jul 2002 Posts: 317 Location: Sanford, ME

you got udev-015 to compile from the ebuild when it was in the portage tree or by hand? =)

Trejkaz · Posted: Fri Jan 30, 2004 5:14 am Post subject:

I just noticed something else curious... it seems now that way too many modules are loaded. For instance I have all three HCD drivers loaded even though I only need uhci_hcd. Also it has loaded every single sound card driver. Maybe I should just remove them all from the build... after all, what's the point of having modules if they're not going to reduce the footprint of the kernel? :-/

infirit · Posted: Fri Jan 30, 2004 5:39 pm Post subject:

ozric100 · Tux's lil' helper Joined: 23 Apr 2002 Posts: 136

I made the switch. I had a problem tho .. It seams that my system would hang on the first time making /devs ... I hit ctl-c and could see that it thought the mtime was +5 hours. data showed that my system was now behind, the hwclock has the right time. I edited /sbinrc and # out the try tar -jxpf .... device line and I got it to boot. I ended up adding m to the swithes and now it working fine. Has anyone had an error like this... My hwclock is set local and my system rc.conf is local as well. It has to be something in the kernel that is messing up the time ... cause rc runs right after init .. I think.

Oh well .... I will say that udev is fast... my system is much responsvie now. Its really noticable.
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Ari Rahikkala · Guru Joined: 02 Oct 2002 Posts: 370 Location: Finland

OK... I decided to start using udev the insane way... after I was reasonably sure that it was working, I commented out the lines in halt.sh that save the device state and replaced /lib/udev-state/devices.tar.bz2 with an empty archive. Don't worry, AFAICT doing this was actually relatively safe since I did back the file up and could have put it back in place inside initrd (I need it for EVMS, and for tweaking I've added a call to sh in the end of its /linuxrc). Well, XFree is running fine, most devices seem to work (I did have to change the path of the mouse device for gpm and XFree, though, but this was only because I didn't want to figure out udev.rules syntax yet). I have a couple of problems, though:

- some modules aren't autoloaded anymore (at last rtc and snd-pcm-oss). This might be the cause of the problem with ALSA, really. I'll just have to figure out what modules I'll have to specify to be loaded...
- ALSA devices nodes aren't created. I'm not sure yet if this will take a lot of tweaking or not. I just modprobed snd-pcm-oss and /dev/dsp (and everything OSS-related) works just fine, but on the other hand, I can't see the normal ALSA devices anywhere... hm...
- trying to fsck /dev/evms/womb (the EVMS device housing my root partition) fails with some kind of an error. This is most probably related to the kernel (2.6.2-rc2-love4, this is the first Love kernel I've used for a while) so I'll try out vanilla before I say anything more about it...
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Ari Rahikkala · Guru Joined: 02 Oct 2002 Posts: 370 Location: Finland

Actually, it seems like the last problem is probably the only one caused by lack of autoloading modules. I was just able to create /dev/sequencer by going through /lib/modules/$(uname -r)/kernel/sound/ and modprobing everything that seemed relevant and it works properly. All of the ALSA device nodes that should exist also do seem to be there, however, they're in /dev when they should be in /dev/snd. /etc/udev/udev.rules is the place for fixing this, AFAIK...
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Ari Rahikkala · Guru Joined: 02 Oct 2002 Posts: 370 Location: Finland

Updated udev to 015 (I kinda assumed that I was running the latest version but it appears I wasn't), downgraded kernel to 2.6.1. ALSA is now in snd/ and the mice in input/ as they should be. I haven't added anything to /etc/modules.autoload.d/kernel-2.6 yet so RTC and ALSA don't work right away after bootup but that's trivial...

... the problem of not being able to reiserfsck /dev/evms/womb, however, is not. I'll recompile reiserfsprogs, reboot and copypaste the error message somewhere. I could work around the problem by, say, adding "touch /forcefsck" in /etc/conf.d/local.stop but that would be unsafe and wrong...
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Ari Rahikkala · Guru Joined: 02 Oct 2002 Posts: 370 Location: Finland

I\ve understood the cause for why /dev/evms/womb can't be fscked now. My initrd (taken almost directly from EVMS 2.2.1) runs evms_activate on the file like it should. devfs was automounted by the kernel and its state wasn't changed between linuxrc's end and init. udev, on the other hand, is stored on a ramfs which is mounted in the beginning of init. That means that it throws away the old /dev/evms/womb. udev (AFAICT) creates a new one but does not activate it. The trivial and slightly unclean fix to this is putting evms/womb in devices.tar.bz2 (that's what I did and I can tell that it works). Moving EVMS2 activation before checkroot is slightly cleaner, but as far as I can see the Right Way would be to check if a ramfs is already mounted on /dev and not mount anything on top of it in /sbin/rc if it is. That way people like I could put stuff in /dev in initrd and still retain it there in init...

* ari contemplates filing a bug, then notices that he's somehow managed to break his system even worse than before and decides to delay that plan... *
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floam · Posted: Sun Feb 01, 2004 6:18 pm Post subject:

regeya · Posted: Wed Feb 04, 2004 5:18 am Post subject:

mmalanc · n00b Joined: 05 Feb 2004 Posts: 1

Robe · n00b Joined: 05 Jan 2004 Posts: 64

I followed the instructions by Decibles and takev . Works great. I ust have one question. Do I need to change my fstab to mount my HD's in udev now that /udev is where all the devices are ?. I changed my mouse in XF86Config to

Option "Device" "/udev/input/mice" and it works just fine. My question is .. should I change my fstab as well I.E. change /dev/hda1 /boot reiserfs noatime, notail 0 0 to

/udev/hda1 /boot reiserfs noatime, notail 0 0

to reflect the directory change ?

thanks .. "And great work all !"

TheCoop · Posted: Thu Feb 05, 2004 5:54 pm Post subject:

udev works fine mounted on /dev. change udev_root to /dev in udev.conf
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Loke · Apprentice Joined: 25 May 2002 Posts: 274 Location: Norway

Ari Rahikkala · Guru Joined: 02 Oct 2002 Posts: 370 Location: Finland

jimnutt · n00b Joined: 21 Jul 2003 Posts: 7 Location: Dedham, MA

Ok, I've got the required baselayout (baselayout-1.8.6.12-r3) but every time I try to boot without devfs mounted I get a reboot just as the initscripts start running (if it manages to show any info, it's too fast for me to see). Anybody else see this? And if so, have you managed to fix it?

jim

Evil Dark Archon · Posted: Wed Feb 11, 2004 12:34 am Post subject:

try removing devfs from the kernel altogether
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