[ltp] suspend-resume problem (A20p)

[Tod Harter]

Hmmmm. I was running 2.4.9 for a good while and it was fine on the A20p. I 
did set some options relating to suspend/resume in the kernel config, but I 
don't think they were really needed. Since then I upgraded to Mandrake 8.1 
(which uses kernel 2.4.8) and it seemed to work fine without any tweaking. 

However, I do note the following:

There were times when resume didn't seem to be eager to happen, and a few 
times my machine did lock up when it resumed, so it wasn't 100% reliable, 
though it never showed the symptoms you're having. Sometimes just hitting the 
"fn" key got me back to life, sometimes I had to hit "fn F4" one or even 
several times (esp after a long suspend) before the machine would wake up. 
Sometimes hitting "fn F3" seemed to work, and occasionally just briefly 
hitting the power button (for maybe 1/2 second) would spark it back to life 
when nothing else would. Now that I have Mdk 8.1 things seem more reliable, 
so its even possible I partly broke something with my custom config.

Since the new version of tputils doesn't work on kernels older than 2.4.16 I 
haven't had a chance yet to back and dig up an older version of that, and so 
I have zero experience with hibernation. Seems like suspend gives at least 3 
days of battery life for me anyway, so its never been a pressing issue. 

Seems weird to me that hibernate would get fouled after a certain amount of 
time though... The only thing I can think of that would be causing that 
problem would be something to do with clock skew. Since hibernation is pretty 
much a BIOS driven thing I don't think the OS itself ever really is aware 
that its happening. My only theory would be that when the OS wakes up it gets 
confused because as far as its concerned the RTC suddenly took a giant leap 
into the future... That might create some problem with open file handles or 
somesuch thing I suppose. Not sure why a certain period of time would be 
necessary for things to get confused though. Another theory would be 
something to do with job scheduling. Maybe cron gets cranky? I'd check my 
system logs after a failure like that and see if perhaps there's a message in 
there relating to time in some fashion.

These are the kernel config settings that Mandrake has in its stock 2.4.8 
kernel config that might relate to APM and suspend/resume. Perhaps this will 
be of some assistance.

#define CONFIG_PM 1
#undef  CONFIG_ACPI
#define CONFIG_APM 1
#undef  CONFIG_APM_IGNORE_USER_SUSPEND
#if  defined(__module__enterprise)
#undef  CONFIG_APM_DO_ENABLE
#undef  CONFIG_APM_CPU_IDLE
#else
#define CONFIG_APM_DO_ENABLE 1
#define CONFIG_APM_CPU_IDLE 1
#endif
#undef  CONFIG_APM_DISPLAY_BLANK
#define CONFIG_APM_RTC_IS_GMT 1
#undef  CONFIG_APM_ALLOW_INTS
#undef  CONFIG_APM_REAL_MODE_POWER_OFF

On Wednesday 26 December 2001 15:05, you wrote:
> My thinkpad has developed a weird problem recently: It won't wake up from a
> suspend - it wakes up from hibernation Ok (well, as long as it hasn't been
> hibernating for > a couple of hours, but its alwys had that problem). It
> suspends Ok, but when I hit the Fn key to bring it back, the CD-ROM drive
> kicks back into life for a second, and that's it - the machine is now
> stuck, (the little crescent moon suspend light is still on) and only
> leaning on the power button for ten seconds, powering on, powering off, and
> powering on again will make it reboot. I upgraded to a new kernel (2.4.16)
> recently, but even after dropping back to the old kernel (2.4.9) the
> problem persists.
>
> Anybody have any idea what could be up with it?

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