8248 Reboot Puzzle

Sam Song samlinuxppc at yahoo.com.cn
Mon Nov 28 14:21:55 EST 2005


Hi all,

I met a reboot puzzle those days. Nearly every boards
of 20 samples had a symptom 
that after issuing a reboot command in Linux land more
than 10 times or so, the
target would encounter some unexpections like hang
after kernel uncompresing or
reset the target when initializing USB[VT6212L] 1.1
host controller. But I never
see any problem if cycle power. Then I have to switch
for a replacement method. 
In 8248 restart function, use a GPIO to pull LOW
POWER_RESET# to get a similar 
result and it did solve the problem. Well, if I use
the GPIO to pull LOW 
HARD_RESET#, problems still existed. I use 2.4.31
kernel.

So I wonder what the problem could be according to
your experience. Can we get
the same result with software as POWER_RESET does? I
also want to know more on the 
difference among software reboot and Power On reset
and Hard reset. I mean the
possibble effect on target running or initialization.

What I wanna to implement is a software power off and
on operation. 
Power-on -> waitting for power button pushing in
u-boot -> boot the target 
-> power off the target in Linux land by pushing the
power button
-> back to u-boot in a software power off state for
next power button pressing
-> ... 

Thanks in advance for any comments/suggestion,

Sam


	

	
		
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