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1  Hardware and U-Boot firmware / Hardware / Re: Prolific Driver for Currentcost device on: March 16, 2010, 10:22:21 AM
I can now access the Prolific PL2303x device  Smiley . I first managed to recompile the Linux kernel and with a small change to the .config file the pl2303 driver was included in the kernel. A good learning exercise since I can now generate  'uImage' from the Linux source.

Following your advice I then downloaded the modules from the sheeva repo and extracted into the lib/modules/ . Then without even having to use modprobe, a reboot magically loaded the pl2303 driver. Not actually magic since the config variable is set


So when the device is seen at boot, the module pl2303.ko, is loaded dynamically.

Excellent - Thankyou Patrick for your assistance.
2  Hardware and U-Boot firmware / Hardware / Re: Prolific Driver for Currentcost device on: March 14, 2010, 05:16:06 PM
Thank you, Patrick for that feedback. I thought that might be the case.  It sounds then like I shall have to learn how to compile my own kernel. I was hoping I would not need to learn how to do that. First time, I am not a *nix expert, this is just a fun project.

If anyone can give me any pointers how best to proceed it would be appreciated, Prolific driver source code? etc etc or if it is possible to add a module without compiling my own kernel?
3  Hardware and U-Boot firmware / Hardware / Prolific Driver for Currentcost device on: March 11, 2010, 11:16:53 AM
I am attempting to attach a "Currentcost" device to the USB port of my sheeva plug but I cannot get it to talk. The Currentcost has a Prolific PL2303x serial to USB conversion chip. I  know block devices work correctly since I can attach USB drives or Pen drives. I am detecting the Prolific chip correctly and I have the latest debian release as shown below.

root@debian:~# lsusb
Bus 001 Device 012: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@debian:~# uname -a
Linux debian 2.6.33 #2 PREEMPT Tue Mar 2 14:27:17 MST 2010 armv5tel GNU/Linux root@debian:~#

When I connect to USB,  the device /dev/usbdev1.2 appears but I do not get a device /dev/ttyUSB0 which is what I would expect. Has anyone connected to the Prolific device through USB?

I have read somewhere that the PL2303 driver is compiled into the kernel. Can someone confirm this is true?  If not, how should I proceed? As far as I can see there is no driver for Linux on the Prolific site.

I have been looking at modprobe and loading a driver module but without a driver that is no good.
4  Hardware and U-Boot firmware / Hardware / Re: Power on Reset on: March 03, 2010, 08:05:59 AM
Problem found.
When you do a reset using the reset pushbutton switch or a soft shutdown the machine re-boots into linux.
When you do a reset by power cycling the machine fails to boot linix because

When you power on you need to do mmcinit twice in order to get the SDcard to work properly.

Then Power on reset works fine.

5  Hardware and U-Boot firmware / Hardware / Power on Reset on: March 03, 2010, 05:45:16 AM
Most of the time I am nice to my plug and use the following to reboot.

shutdown -r now

Occasionally, things go awry and I have to insert a paperclip and do a reset.

That is fine and the machine reboots (Fastish SD card, 20 secs or so). Very occasionally I turn the plug off and when I turn it back on it boots only into the Marvell >> prompt. Is there a way to boot the kernel from power on.

This is important to me because I intend to have a plug server in France and we get regular power glitches. Sadly my paperclip is not long enough  Roll Eyes so if there is no solution I will have to go for a partial solution of a UPS.

6  Linux Stuff / Kernel / Re: new release on: March 03, 2010, 04:38:03 AM
Thanks for the advice regarding "su" failure. The problem is now resolved. Should have RTFM  Embarrassed though if I had FTFM it would have saved some time.

echo 32768 > /proc/sys/vm/mmap_min_addr

This also enables user login by SSH and subsequent su to any user.  Smiley  Thankyou for your assistance.
7  Linux Stuff / Kernel / Re: new release on: March 02, 2010, 10:56:21 AM
I seem to have missed the README but I am sorry to say this does not help.
cat /proc/sys/vm/mmap_min_addr
If it's not set to 32768 you need to get it set to 32768.

I am sure this is good advice BUT Sadly no such file "10-process-security.conf" exists anywhere on my filesystem.
Any more suggestions?

From the README
####### change vm security settings
# Due to changes in vm security a change must be made in /etc/sysctl.d/10-process-security.conf.
# vm.mmap_min_addr should be set to 32768 (This change is safe for any kernel version).
# If this is not done it is likely that you will not be able to login remotely.
# Although you should still be able to login as root on the main console.
8  Linux Stuff / General Linux questions / Re: SSH, su, adduser do not work on debian on: February 25, 2010, 11:24:34 AM
I don't think the problem is an SSH problem although it manifested as one since I created a user with an associated authorized_keys file but could not get secure SSH access. Delving deeper I think the problem is with the kernel and I have made some comments on the Kernel forum entry.

For now I am going back to an old kernel until this bug is fixed. Maybe somebody could confirm that they are getting similar problems. Surprising this has not been spotted by others ?!

Cannot SU between accounts (fails password authenticatoon)
Can serial console login as root or as any valid user
Can SSH password login
Can SSH login by PPK authentication.
Cannot SU between accounts
Can serial console login ONLY as root
Can SSH login only as root with a password
Cannot SSH login as any other user either by password or with PPK authentication

Although not possible to SU between accounts, you can login as root and then "su" to a user. But after that you cannot "su root" or "su" to any other user. su to another user, of course, does not require a passwd, so maybe the problem is more to do with passwords.
9  Linux Stuff / Kernel / Re: new release on: February 25, 2010, 09:42:44 AM
Further investigation reveals that su "stopped working" between and However, it was not fully working on version

On    " su <user>"    Does nothing, no error, no request for password, nothing

On you can login as root and " su <user>"

This does as it should, correctly logging you in as that user, without asking for a password. BUT it is then impossible to use su to get back to root or to su to any other user. It does ask for a password but entering the correct password gives

su: Authentication failure
10  Linux Stuff / Kernel / Re: new release on: February 25, 2010, 07:57:56 AM
I have just discovered that for this release the command 'su' does not work. Also, even after creating a new user (adduser) it is impossible for that user, or any user other than root to login, either from a serial terminal or remotely.

I have done some testing

Kernel   su <user> works OK
Kernel 2.6.31   su <user> Fails
Kernel   su <user> Fails
Kernel   su <user> Fails

So presumably something broke between 30.1 and 31. I am in severe doubt about this as I cannot imagine somebody else has not noticed it, but it is definitely what is happening to me.

11  Linux Stuff / General Linux questions / Re: SSH, su, adduser do not work on debian on: February 25, 2010, 06:28:03 AM
Just to clarify

Typo, I do have "authorized_keys" file
sshd is running, must be since I can login as root. Port 22.

12  Linux Stuff / General Linux questions / SSH, su, adduser do not work on debian on: February 24, 2010, 01:41:15 PM
Raw installation. I have of the kernelon the SD cqrd of my plug.
I am new to debian but have used fedora/redhat.

Why oh why

1) does 'su' not do anything, presumably related to the fact that
2) adduser does not create a user that can login
3) and SSH does not appear to work

The user is in the /etc/passwd file
I have a valid /home/user/.ssh/authorized_users file

Still, I can only login remotely as root with a password.

13  Hardware and U-Boot firmware / U-Boot stuff / Re: Dual boot NAND and SDCARD on: February 24, 2010, 05:34:29 AM
Pingtoo ... I notice in your command sequence you set the mainlineLinux variable, save it and then do a reset.

Why is the reset operation necessary? What is tit that the boot loader is doing?

I can tell you that if you don't do the reset it does not work. Hangs after loading the kernel .....

This means dual booting is IMPOSSIBLE;
14  Linux Stuff / Kernel / Re: Problem accessing FAT32 formatted drive on the USB port on: February 23, 2010, 10:28:57 AM
I have now got hold of the latest and greatest kernel which does have vfat support.  Problem solved. In fact all the following

nodev   sysfs
nodev   rootfs
nodev   bdev
nodev   proc
nodev   tmpfs
nodev   debugfs
nodev   sockfs
nodev   usbfs
nodev   pipefs
nodev   anon_inodefs
nodev   rpc_pipefs
nodev   inotifyfs
nodev   devpts
nodev   ramfs
nodev   nfs
nodev   nfs4
nodev   jffs2
nodev   oprofilefs
nodev   ubifs
15  Hardware and U-Boot firmware / U-Boot stuff / Re: Dual boot NAND and SDCARD on: February 23, 2010, 10:23:47 AM
 Smiley At last it works. Thankyou Pingtoo so much.

So I need to be very careful about spaces in the argument list and simplify my arguments as much as possible. Statements about woods and trees. This is the problem with doing things by rote from FAQ/HOWTO examples when you dont totally understand what you are doing.

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