Linux Mint 7 freeze problem

[exvagabond]

Hi. I recently installed Linux Mint 7 onto a system. For a week or two I have not experienced any problems. Then recently the system has frozen up a few times. Originally I thought the freezing was random, but I seem to have tracked down a root causes. It just does not make much sense.

I have a few microprocessors I program from my computer. The microprocessors attach via a USB port. When attached, the microprocessor registers as a USB device, and to get serial output from the microprocessor I read the USB port like the following:

# Setup port with UART baud rate
stty -F /dev/ttyUSB0 raw 115200
# read port
cat /dev/ttyUSB0

When I read from my microprocessors using cat, a few minutes or less later the system freezes. Having the devices simply attached to the computer does not cause the problem; i have to be using cat on them.

When the system freezes the keyboard and mouse do not respond. I cannot ssh into the machine, as it says there is no route to the frozen computer. I looked through the /var/log/kern.log /var/log/messages /var/log/syslog files, and there is nothing in them about the freeze. (The last event listed is the plugging in of my microprocessors). One more thing: the microprocessors have an LED which blinks when they are sending serial data to the computer. When I do not cat, the led is not active. When I use cat, it blinks rapidly. When the computer freezes when I am using cat, the LED is again inactive. That is, the computer no longer is reading data.

I cannot figure out this problem, so if anyone has a hint, that would be great. I do not believe the computer hardware is at fault, as I was using Mandriva 2008.1 before this and never had a problem with the microprocessors. I also use Linux Mint 6 XFCE on my laptop and have no problems with the microprocessors.

- Quatre

[DrHu]

I have a few microprocessors I program from my computer. The microprocessors attach via a USB port. When attached, the microprocessor registers as a USB device, and to get serial output from the microprocessor I read the USB port like the following:

Might be useful to know which microelectronics you are programming..
--you also haven't said if you can use programming station with an ICE or IDE setup to see the external device contents, which might be a big help if the system is dropping the device or hanging up for some reason, like watchdog timers etc

Have you CAT'd to a *.txt file to see what happens on the port
cat /dev/ttyUSB0 >dumpuart.txt
--should be better than looking through the system logs..
http://www.microchip.com/forums/tm.aspx ... 22&mpage=2
--see xiaofan relating to

Regarding suspend and resume, I just found out the relevant case under Ubuntu 7.04. The bootloader application fsusb works fine under Ubuntu 6.06 but not in Ubuntu 7.04. lsusb does not show the device and fsusb can not find the device either. However Greg KH's USBview can find the device.
...
linux kernel USB developer Alan Stern then advised me to build the kernel again with CONFIG_USB_SUSPEND disabled. This solved the problem.

--might have something to do with the OS kernel build for usb devices, or the external device itsel has some quirky usb software control being needed..

Possibilities for hang-up..
Thinking power control, acpi services within the Linux OS
--could look through mint for services added or installed programs added
http://ubuntuforums.org/showthread.php?p=1990911
--via synaptic (mint menu>Package Manager) Status>Installed
--via the terminal with dpkg --get-selections | grep -v deinstall > installed-files ; this user's post, I like the command-line version, it is quicker and maybe easier to read/more compressed view of the data..

I suppose one could suggest a fresh usb cable or a different usb port for the external device, physical connections (especially often removed ones can fail fairly easily..

[exvagabond]

The microprocessor platform I am using is based on the AVR family, specifically atmega1281. There is a USB programmer which programs the microprocessor, and forwards microprocessor UART output over USB to the host PC. This means that even if the microprocessor were doing weird things (resetting, etc), the USB programmer isolates the microprocessor from the PC. The /dev/ttyUSB endpoint remains on the PC as long as the programmer has power, regardless if a microprocessor is attached or not. I only use command line tools to program the microprocessors, namely gcc and avrdude.

Thanks for the suggestions. So far I have tried the following to fix the lockup problem without success:
- Try connecting the microprocessors on other USB ports.
- Disable acpid and apmd from starting up using the Services tool, then restart.

I am now compiling a kernel without usb suspend support to see if that fixes the problem. If that does not work, unless there are any other suggestions for things to try, I will probably just move back to Linux Mint 6 and hope for the best.

As another observation, I think that reading from only one of the microprocessors at a time does not cause the problem. It seems that only when I read from two at the same time that lockups arise.

- Quatre

[exvagabond]

The freeze problem persists even after compiling and running a kernel without usb suspend support. I will drop back to Linux Mint 6 XFCE and hope for the best.

[scarr500]

This worked perfectly in mint cinnamon. Hope this helps:

http://www.reddit.com/r/linux4noobs/com ... nfig_file/

[zerozero]

certainly it won't help. this topic is 3 years old!! please don't bump old topics.
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