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-   -   Rebooting quick-fix (https://talk.maemo.org/showthread.php?t=37752)

bsving 2009-12-19 12:27

Rebooting quick-fix
 
The most common rebooting issue is the "32wd_to" (HW watchdog). A quick fix for this is described (buried) at https://bugs.maemo.org/show_bug.cgi?id=6334

Please, read through all the comments in that thread, and in particular read everything from Eero Tamminen (Nokia) at least three times :)

First you need to check if your rebooting problems are 32wd_to. This is done by opening the x-terminal just after a random reboot and typing:
"cat /proc/bootreason"
If the result is "32wd_to", then this quick fix will work.

The quick fix consists of disabling the device going to "deep sleep", and is done by:
Quote:

"enable_off_mode" to "0" (as root):
- To do this temporarily, do "echo 0 > /sys/power/enable_off_mode"
- To do this permanently, change the "enable_off_mode" setting in
/etc/pmconfig file to "0" and reboot the device.
The down side is that the battery will drain quicker when the phone is unused. I have tried it some days now, and with normal (phone)use it will last a day at least. No change when used continuosly.

My experience with this fix is a rock stable device, which is nice to have untill the bug is fixed permanently by Nokia :)

The device will not reboot while connected to a USB cable to a PC (it will reboot while connected to a charger). While doing the quick-fix, it is an idea to keep it connected.

Also, frequent reboots will sooner or later corrupt the file system, possibly "bricking" the device. After ANY random reboot it is therefore a good idea to use the on/off button for a cold reboot. It is also a good idea to reflash the device before this fix, to be sure the file system is OK, both firmware and eMMC.

From the Nokia board http://discussions.europe.nokia.com/...cending&page=1
After 17 random reboots in a row, the N900 is bricked. The link shows how to unbrick it. The importance of doing a manual cold restart (off/on) with power button is clearly strengthened.

Alex Atkin UK 2009-12-19 12:33

Re: Rebooting quick-fix
 
I still find it questionable if this in fact CAN be fixed in software, other than your workaround which is not practical in the long term due to the extra battery usage.

If it happens to some peoples devices from fresh flashing and others never suffer it at all, it sounds more like a hardware problem. All I can think is Nokia are hoping its a minor glitch in the CPU that can somehow be bypassed using some sort of microcode update, though do ARM CPUs even have a microcode?

bsving 2009-12-19 12:56

Re: Rebooting quick-fix
 
I don't pretend knowing what is going on internally with this watchdog, but as I understand it is essentially just a timer that is triggered (or not). I don't see any reason why this cannot be fixed with better drivers, since the reason could very well be that the driver does not "pet" it often enough when in normal operation, or the signal is a tad too short or some similar thing. The watchdog say "go to sleep" while the software is still in the middle of an operation. Again, not pretending I know something I don't, I would assume this is normal driver tuning.

Seemingly identical hardware often behave different, particularly regarding timers and interaction with software, this I do know by experience.

I don't think Nokia would say they believe they can fix this, if they actually believe opposite. But there is no guaranty that it actually will be fixed, intill it is, so I keep my fingers crossed :D

mysticrokks 2009-12-20 18:06

Re: Rebooting quick-fix
 
ok erm i am a total newbie on this,, what do i have to type into the x terminal to make this a tempoary fix as my machine is rebooting and stuff

is it just this

echo 0 > /sys/power/enable_off_mode

and what do i do to switch it back?


ok again i am a serious noob- permission denied(proc bootreason) what do i need to do to use to be able to access this sort of stuff..

gravis86 2009-12-20 18:19

Re: Rebooting quick-fix
 
I'm trying to do this, but I keep getting "Permission denied". What do I need to do to gain permission?

bsving 2009-12-20 18:21

Re: Rebooting quick-fix
 
Quote:

Originally Posted by mysticrokks (Post 435510)
ok erm i am a total newbie on this,, what do i have to type into the x terminal to make this a tempoary fix as my machine is rebooting and stuff

is it just this

echo 0 > /sys/power/enable_off_mode

and what do i do to switch it back?


ok again i am a serious noob- permission denied(proc bootreason) what do i need to do to use to be able to access this sort of stuff..

First you have to install a small app to get root access:
http://wiki.maemo.org/Root_access

Then open the terminal (x-term) and write:
root
then
echo 0 > /sys/power/enable_off_mode

To get it back to original condition, just reboot or write:
echo 1 > /sys/power/enable_off_mode

By far the best option is to make it permanent in the config file, as described.

mysticrokks 2009-12-20 19:14

Re: Rebooting quick-fix
 
thank you dude..


ok i take it rootsh is the best way- and type root b4 any command..


btw why is the permanent way better..

what is the difference(not specifics)- in practical terms.

bsving 2009-12-20 19:20

Re: Rebooting quick-fix
 
Quote:

Originally Posted by mysticrokks (Post 435583)
thank you dude..


ok i take it rootsh is the best way- and type root b4 any command..


btw why is the permanent way better..

what is the difference(not specifics)- in practical terms.

Then you only have to do it once, and the change is permanent (untill you change it back), othervise you have to do it every time you reboot (turn on-off) etc. I don't think here are any other difference.

mysticrokks 2009-12-20 19:59

Re: Rebooting quick-fix
 
ok i installed rootsh

it is still saying permission denied

after

root

/proc/bootreason

bsving 2009-12-20 21:35

Re: Rebooting quick-fix
 
Quote:

Originally Posted by mysticrokks (Post 435627)
ok i installed rootsh

it is still saying permission denied

after

root

/proc/bootreason

Sorry, It is:
cat /proc/bootreason

I will update this. (you don't need root access for this though)


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