Comment 0 for bug 160763

This problem has been posted in Ubuntuforums (http://ubuntuforums.org/showthread.php?t=600450), but got no answer.

My Acer Aspire 5720 running Ubuntu Gutsy 7.10 is unable to resume from a standby when another standby/resume has occurred. The power LED turns from blinking orange to stable green, but screen backlight remains off and - I suppose - the processor fan stays off too. I can hear the hard drive and CD-ROM spinning up, but the system is completely unresponsive. I have to turn it off pressing the power key long enough.

On Windows XP and Vista, standby works OK.

These are the attempts made so far. Where not specified, nothing changed in the behaviour.
- adding "ec_intr=0" to the boot cmdline;
- adding "acpi_osi=!Linux";
- executing Ubuntu in single-user mode, using /etc/acpi/sleep.sh to sleep;
toggling the following flags in /etc/default/acpi-support, one by one:
- ACPI_SLEEP_MODE=standby -> the script stops and says "echo: write: No such device" writing 'standby' to /sys/power/state
- SAVE_VBE_STATE=false
- POST_VIDEO=false
- USE_DPMS=false
- DISABLE_DMA=true
- RESET_DRIVE=true
- ENABLE_LAPTOP_MODE=true
- DOUBLE_CONSOLE_SW=true
- toggling more than one flag like described here: http://de.wikibooks.org/wiki/Asus_W3N-Kompendium:_Ubuntu_Suspend_to_Ram -> hangs on first resume
- disabling all services in /etc/rcS.d, then killing most of the processes, then removing most of the modules;
- adding "noapic nolapic" to the boot cmdline -> hangs on first resume;
- adding "pci=routeirq" to the boot cmdline;
- toggling BIOS SATA emulation from AHCI to PATA;
- disabling all scripts in /etc/acpi/{suspend,resume}.d -> apart from the screen unable to work at first resume, nothing changed;
- upgrading BIOS from 1.14 to 1.19;

I followed the instructions at https://wiki.ubuntu.com/DebuggingKernelSuspend. If I execute that command even for first standby, at next reboot I have these data:
Magic number: 0:35:185
hash matches drivers/base/power/resume.c:57
hash matches device device:44

Any help is VERY appreciated! This is definitely the bug that keeps me to using Linux for everyday work...