Missing ttyAMA0 device in rootfs

[Loïc Minier]

Hi,

Sagar Kadam reported on linaro-dev@ that he was getting an error message on boot:
Starting Boolog daemon: bootlogd: cannot find console device 204:64 under /dev

This appears to be due to /dev/ttyAMA0 being missing from the OE rootfses, or perhaps some other device node (/dev/stdin and the like?). I've confirmed that /dev/ttyAMA0 isn't in core-image-minimal-genericarmv8-20121124161453.rootfs.tar.gz.

He proposes setting CONFIG_DEVTMPFS_MOUNT=y which might be too intrusive a change IMHO.

Cheers,

[Sagar Kadam (sagar-kadam)]

There are multiple approaches, using which this problem can be resolved:
1. Add the device into device_list file in /etc of OE File system
2. Add an entry into /etc/fstab so that the devtmpfs is auto-mounted during boot-up
3. Provide a kernel command line argument so as to mount devtmpfs.

Please suggest which is a suitable way of doing it.

Cheers,
Sagar Kadam

[Riku Voipio (riku-voipio)]

CONFIG_DEVTMPFS_MOUNT=y is already set in our ubuntu kernels by default, so I guess it's safe for OE as well.

Riku

[Marcin Juszkiewicz (hrw)]

CONFIG_DEVTMPFS_MOUNT=y is set in OpenEmbedded. Sagar's problem is that he is using own kernel without that option.

[Marcin Juszkiewicz (hrw)]

Sagar: use "deftmpfs.mount=1" kernel argument. We want to have as minimal set of changes as possible. Taking care of device_table is not one of them.

OE kernels have mounting of devtmpfs enabled by default. I suggest do the same with external ones.