[Ubuntu Wiki] Update of "DebuggingKernelSuspend" by penalvch

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Sat Nov 14 01:02:05 UTC 2015


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The "DebuggingKernelSuspend" page has been changed by penalvch:
http://wiki.ubuntu.com/DebuggingKernelSuspend?action=diff&rev1=47&rev2=48

Comment:
Added s2ram.txt link from kernel.org so folks don't have to dig for files that they don't know the exact location of.

  
  == "resume-trace" debugging procedure for finding buggy drivers ==
  
- Resume problems are difficult to debug.  The approach used here needs to make notes on progress during resume and be able to recover them after a manual reboot.  But there is no non-volatile storage available at the time resume is bringing up your computer. The only hardware on a PC motherboard that retains information across power cycles is the real time clock (RTC), so that is what is used. For those that want to know the details, read Documentation/power/s2ram.txt in your kernel sources. The implementation of suspend/resume debug trace is in drivers/base/power/trace.c.
+ Resume problems are difficult to debug.  The approach used here needs to make notes on progress during resume and be able to recover them after a manual reboot.  But there is no non-volatile storage available at the time resume is bringing up your computer. The only hardware on a PC motherboard that retains information across power cycles is the real time clock (RTC), so that is what is used. For those that want to know the details, please read Documentation/power/s2ram.txt in your kernel sources, or see [[https://www.kernel.org/doc/Documentation/power/s2ram.txt|here]]. The implementation of suspend/resume debug trace is in drivers/base/power/trace.c.
  
  Caveat Emptor: Using the following debug suggestions will radically change the values in your RTC chip, so much so that your file system will think it has been eons since the last fsck. You can avoid a long fsck delay by using 'tune2fs'. For example, 'tune2fs -i 0 /dev/sda1' disables fsck on boot.  But first you'll want to use 'tune2fs -l <partition>' to find your current settings - look at the "Check interval" setting.
  



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