[lug] logging missing 2.6 kernel modules

D. Stimits stimits at comcast.net
Mon Jun 13 11:40:25 MDT 2005

Zan Lynx wrote:
> On Sun, 2005-06-12 at 23:25 -0600, D. Stimits wrote:
>>Lee Woodworth wrote:
>>>In reviewing the hotplug and udev stuff, I was reminded of
>>>some things I have seen on the web that apply:
>>>   Kernel version 2.6 will not automaticlly load device drivers
>>>   when a related device node is accessed. The major reason
>>>   being that there is interest in having device major/minor
>>>   become dynamially allocated. For example the device mapper
>>>   (dm_mod) already uses a dynamic minor number for
>>>   /dev/mapper/control.
>>>You may be interested in this excerpt from the udev FAQ:
>>>   Q: But udev will not automatically load a driver if a /dev node is opened
>>>      when it is not present like devfs will do.
>>>   A: If you really require this functionality, then use devfs.  It is still
>>>      present in the kernel.
>>As far as I know I'm not using udev. For the old devfs it's easy to 
>>check (not using it), I'm coming up blank trying to figure what kernel 
>>config is for udev.
> There is no kernel configuration for udev.  The "u" in udev is for
> user-space.  The only bit that is done in the kernel is hotplug
> notification.  udev picks up static devices through boot scripts, called
> hotplug or coldplug, depending on the distro.  The boot scripts scan for
> hardware and simulate hotplug calls for the hardware.
> For Gentoo, they have a coldplug script but recommend loading the
> modules statically if you know what you've got plugged in, since it is
> faster.

Sounds like I'm missing the coldplug scripts, as my hotplug obviously 
isn't doing it. Or perhaps there's a config somewhere for hotplug on 
fedora that does not depend on hotplug events. The part where it scans 
for non-hotplug hardware during boot is either missing, or part of a 
config I can't find for the joystick. I'd think by now the sblive would 
be detected in distros (meaning the joystick port, not just sound).

>>>   Q: But wait, I really want udev to automatically load drivers when they
>>>      are not present but the device node is opened.  It's the only reason I
>>>      like using devfs.  Please make udev do this.
>>>   A: No.  udev is for managing /dev, not loading kernel drivers.
>>I'm actually hoping for some *other* mechanism to do this, not udev.
> If you set the option in the kernel configuration, it will still call
> out to modprobe to load things like SCSI or network drivers.  If that
> isn't working, it could be that modprobe is disabled by your distro
> writing an empty line into /proc/sys/kernel/modprobe.  Make sure that's
> set to /sbin/modprobe.

Nope, I checked this a while back, it is there and runs fine. I even 
reported it in an earlier email. Modprobe might have some further 
config, but as it is it runs and fails (why did they have to remove 
/etc/modules.conf? Such a tragedy of complications).

D. Stimits, stimits AT comcast DOT net

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