# ACPI sleep regression on 2.6.20 -> 2.6.21

## agnitio

Since I upgraded to kernel 2.6.21 ACPI sleep (suspend to ram) seems to have regressed, it previously worked like a charm but now I'm having trouble both with going to sleep and waking up. I can't really figure out the determining factor, but sometimes the system hangs when trying to sleep (most often when using "echo mem > /sys/power/state"), and other times it sleeps just fine (most often when issuing sleep mode from gnome-power-manager).

However, when I try to wake it up the screen won't re-initialize and just stay black, if I blindly issue a "/etc/init.d/xdm restart" the screen goes back up and the system is fully working. If I revert back to the older 2.6.20 kernel the issue is resolved, using the same version of the proprietary ati-driver.

The only change between 2.6.20 and 2.6.21 configs are that in 2.6.21 I enabled "tickless system" and "high-res timer support", my next experiment is to disable theese again and see where it leads. Meanwhile, I would like to see if anyone has experienced the same issue with the 2.6.21 kernel.

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## trilexx

same here.

suspend to ram worked fine before. I did the upgrade because 2.6.21 contains some fixes for ACPI related issues like fan control etc. however, after the upgrade suspend didn't work anymore. somtimes I can suspend, sometimes not. Resume doesn't work at all.

cheers

trilexx

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## IvanMajhen

I also had problems with sleep with 2.6.21 kernel. It worked without dyntick and hrt, but with them it needed about 20sec to resume. 

My problem was processor.ko. If unloaded before suspend2ram (with dyntick-hrt enabled) suspend and resume worked in seconds.

So i just compiled processor and thermal as modules, and edit hibernate script to unload them before suspending. I also patched klaptop to use hibernate-ram script when suspending. 

I have intel card.

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## Evincar

Same experience as Trilex, 2.6.21 ruined my hibernate-ram. Hibernate only works without tickless and HRT, making 2.6.21 useless  :Sad: .

IvanMajen, can you give more details on your hardware and /etc/hibernate/ram.conf ? I am kinda disturbed by this setback...

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## trilexx

Well, suspend/hibernate is really a pain in the a**. I switched to the suspend2 sources when suspend2-2.6.21-r3 was out. I could finally get it working. Suspend to RAM, and even hibernate (with minor issues here and there though). But now, with every kernel upgrade: suspend2-2.6.21-r4 to r6 everything got worse. I don't know what they keep changing, but as soon as I got it working again, all the work will be wiped out by the new kernel. Although the logs look fine you will have to start from the beginning when switching to a new kernel. You will have to find out which module makes it puke now and this will take you a long time, especially if you have to do it the hard way by really suspending/resuming...

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## devsk

it seems like something in 2.6.21-r2 broke suspend-to-ram.

https://bugs.gentoo.org/show_bug.cgi?id=184852

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