Re: after reboot rtc dsp missing from /dev
On Wed, Feb 02, 2005 at 09:39:09PM +0530, Prashant kumar wrote:
> Everytime I reboot my system I find some useful entries such as dsp,rtc
> .. not in /dev
My understanding is that udev is a cleaner replacement for
now-depreciated devfs. One of the design goals is that /dev/ should
only contain nodes for devices that are actually installed (and
recognized by the kernel).
So, does your kernel know about your soundcard and your RTC?
> moreover ./MAKEDEV audio too doesn't work as a work around I create
> these device entries using mknod.
>
> though MAKEDEV not working is a problem in itself but more importantly
> why should those entries vanish on reboot ?
Hmm. are those devices present in /.dev/? (during boot, udev "bind
mounts" the normal, static /dev/ to /.dev/, effectively relocating it.
I don't know if udev maybe only creates /dev/ entries (in a new /dev/,
after the bind mount) for devices which are present in the
old-/dev/-now-called-/.dev/ tree.
> I guess following inforamtion should help:
>
> During boot I get following warning
>
> warning: .udevdb already exists on old /dev !
Donno anything about that..
> df -h gives followingFilesystem
> Size Used Avail Use% Mounted on
> /dev/sda6 5.5G 3.9G 1.4G 75% /
> tmpfs 245M 0 245M 0% /dev/shm
> /dev/sda2 28G 17G 9.6G 64% /home
> /dev/sda8 21G 12G 8.1G 58% /backup
> /dev 5.5G 3.9G 1.4G 75% /.dev
> none 5.0M 2.8M 2.3M 56% /dev
That looks good, similar to my system.
> also output of mount command is following
>
> /dev/sda6 on / type ext3 (rw,errors=remount-ro)
> proc on /proc type proc (rw)
> sysfs on /sys type sysfs (rw)
^^^^^
Good, and necessary for udev to populate /dev/.
> devpts on /dev/pts type devpts (rw,gid=5,mode=620)
> tmpfs on /dev/shm type tmpfs (rw)
> /dev/sda2 on /home type ext3 (rw,noatime)
> /dev/sda8 on /backup type ext3 (rw,noatime)
> /dev on /.dev type unknown (rw,bind)
> none on /dev type tmpfs (rw,size=5M,mode=0755)
Right, that's /dev/ being relocated as /.dev/ and a new dynamic /dev/
being created.
Hope that helps.
Justin
Reply to: