Touch Bootstrapping debian wheezy (problems)

[Aydan]

I tried to bootstrap debian wheezy armhf onto my kobo touch N905B and it is sort of working.
The init scripts run but that's about it.
I say sort of because the udevd #175 which comes with wheezy doesn't like kobo's 2.6.35 kernel, so I had to deactivate it.
And without udev a lot of stuff (serial port for console, usb network, even mmcblk* is misisng) just doesn't work because /dev is not fully populated.
So now my question is:
How to solve this dilemma the easiest way?
Which kernel version is needed for udev #175 to work?
Or which udev version will run on the 2.6.35 kernel?
How hard is it to patch a newer kernel to use for kobo?

Regards
Aydan

[pazos]

Maybe kobo kernel lacks support of devtmpfs (needed for udev). In my experience is easier to add support to devtmpfs to kobo kernel than to get a mainline kernel to work with kobo hardware.

First, I would check if the kernel support devtmpfs or this option can be enabled via menuconfig. If devtmpfs is not supported you have two options:

- use mdev + tmpfs to populate /dev
- backport devtmpfs to kobo kernel

If you want to backport devtmpfs here is an example that WarheadsSE did for OXNAS kernel in order to be able to run udev ->> https://github.com/WarheadsSE/OX820-2.6-linux

[Aydan]

The thing is that the touch IS running udev in version 142. That's what's throwing me.

[pazos]

Yes, old versions of udev didn't rely on devtmpfs.

See this >> http://pikachu.3ti.be/pipermail/rear...ry/001892.html
and this >> https://lkml.org/lkml/2012/10/3/618

You can try with debian squeeze, I think udev may work if is below 175

[Aydan]

So compiling udev 174 should get me running again.
Thanks for the pointers.

[Aydan]

I tried with udev 174:
It compiles but it's missing files.
This is what I get on startup:

[info] Using makefile-style concurrent boot in runlevel S.
starting udev
custom logging function 0x28008 registered
selinux=0
runtime dir '/run/udev'
calling: info
/etc/init.d/udev: 290: /etc/init.d/udev: /lib/udev/create_static_nodes: not found
[ ok ] Starting the hotplug events dispatcher: udevd.
/etc/init.d/udev: 301: /etc/init.d/udev: /lib/udev/write_dev_root_rule: not found
[ ok ] Activating swap...done.
[....] Cleaning up temporary files... /tmp/etc/init.d/checkroot-bootclean.sh: 215: /etc/init.d/checkroot-bootclean.sh: cannot create /dev/null: File exists
/etc/init.d/checkroot-bootclean.sh: 215: /etc/init.d/checkroot-bootclean.sh: cannot create /dev/null: File exists
.

I couldn't find any information on where to get those files from. I also couldn't find any info on where to get the source for libudev0 from.
So now I'm stuck again.

Regards
Aydan

[pazos]

You should try mdev, is enough for kobos hardware. Just deactivate udev and install busybox for armhf

I didn't find any guide for debian, but here is pretty good information: http://www.snafu.priv.at/interests/debian/mdev.html

[Aydan]

I tried mdev and it works.
I get a serial console where I can login, but as soon as I plug in the usb the kernel oopses.
see kernel-oops-2014-06-17.txt.
I'm using the original kobo kernel from my other KT SD-card as well as the uboot and whatever from the unpartitioned area.

I am now out of ideas, again. I'm not really firm in the ways of the linux kernel.

Regards
Aydan

[pazos]

Please check that you start mdev AFTER moun /proc and /sys and enable dynamic device updates with echo /sbin/mdev > /proc/sys/kernel/hotplug

oops seems related to hotplug
I hope it works

[Aydan]

Thanks for all the pointers you're giving me. I really do feel like a NOOB here

mdev -s runs after the filesystems are mounted and
"cat /proc/sys/kernel/hotplug" gives me "/bin/mdev", which is where mdev resides.

this is my /etc/init.d/mdev:

#! /bin/sh
### BEGIN INIT INFO
# Provides:          mdev
# Required-Start:    mountdevsubfs
# Required-Stop:
# Default-Start:     S
# Default-Stop:      0 6
# Short-Description: register mdev hotplug handler
# Description:
### END INIT INFO
# /etc/init.d/mdev
#
echo mount:
mount

# Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting mdev"
    echo /bin/mdev > /proc/sys/kernel/hotplug
    /bin/mdev -s
    ls /dev
    ;;
  stop)
    echo "Stopping mdev"
    ;;
  *)
    echo "Usage: /etc/init.d/blah {start|stop}"
    exit 1
    ;;
esac

exit 0

There's still some debug stuff in there.

EDIT: Hotplug seems to work. I plugged in an SD-card and the correct /dev/ entries showed up. Loading the wifi module also produced a /dev/eth0 node.

Regards
Aydan

[pazos]

Sorry Aydan, but I'm out of ideas too. I used mdev in a bunch of embedded devices ( an iomega iconnect, an insignia infocast and a parrot df3120 photo frame ) and everything went smooth..

Could you paste here your mdev.conf (under /etc) ?

Are you using modules? Are installed in default path ( /lib/modules/`uname -r`/)? Can you run depmod -a in your kobo?. You can try if loading arco_*.ko and g_ether.ko modules before plugin usb cable makes any diference.

You can also build busybox yourself (cross-compile with kobo armhf toolchain) and disable features in mdev ( just enabling mdev itself )

[Aydan]

Thanks for the help anyway.
I'm running without modules except for the ones in the /drivers folder. The directory for the modules doesn't even exist. The one on the original kobo only contains an empty file named modules.dep.bb
i did copy the folder form the original sdcard and ran "depmod -a" which gave me the following:

WARNING: could not open /lib/modules/2.6.35.3-850-gbc67621+/modules.order: No such file or directory
WARNING: could not open /lib/modules/2.6.35.3-850-gbc67621+/modules.builtin: No such file or directory

I won't even have to crosscompile because I have an arm7 board (cubox) to compile on.

Regards
Aydan

[Aydan]

I suspect the kernel tries to call something that isn't there in my installation although it's the original kernel. Do you have any idea how I could find out what's going on? I'm a total noob kernel wise.

Regards
Aydan