Re: Device file not appearing

[Gregory Anders <greg@gpanders.com>]

On Wed, 17 Mar 2021 17:16:04 +0100, Greg KH <greg@kroah.com> wrote:
>udev does not do device node creation anymore (as of a decade or so),
>you should make sure devtmpfs is mounted at /dev/ in order for this to
>work properly.
>
>good luck!
>
>greg k-h

I switched over to using the miscdevice API and the situation is the 
same. Nothing under /dev, but I can see my device under /sys/dev/char 
(it now also exists under /sys/devices/virtual/misc/, as expected).

I verified that devtmpfs is enabled in the kernel config 
(CONFIG_DEVTMPFS=y and CONFIG_DEVTMPFS_MOUNT=y) and also see that it is 
mounted on /dev:

     # cat /proc/mounts
     root@xilinx-kcu105-2020_2:~# cat /proc/mounts
     192.168.0.116:/data/nfs/root / nfs rw,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.0.116,mountvers=3,mountproto=tcp,local_lock=all,addr=192.168.0.116 0 0
     devtmpfs /dev devtmpfs rw,relatime,size=1026312k,nr_inodes=185478,mode=755 0 0
     proc /proc proc rw,relatime 0 0
     sysfs /sys sysfs rw,relatime 0 0
     tmpfs /run tmpfs rw,nosuid,nodev,mode=755 0 0
     tmpfs /var/volatile tmpfs rw,relatime 0 0
     tmpfs /dev tmpfs rw,relatime,size=64k,mode=755 0 0
     devpts /dev/pts devpts rw,relatime,mode=600,ptmxmode=000 0 0

I notice that it lists /dev as both devtmpfs (line 2) as well as tmpfs 
(the second line from the bottom). Could that be an issue? I'm not sure 
how or why /dev is being mounted as tmpfs in addition to devtmpfs.

Thanks,

Greg

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