[Bug 160763] Re: Acer Aspire 5720 hangs on second resume from suspend, i.e. suspends only once [BIOS PROBLEM]

[Maxim Levitsky]

** Description changed:

  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.
  
  *UPDATE*
  
  this is BIOS problem. system hangs early and doesn't pass control to Linux.
  Linux has no chance to bring system back.
  
- It not possible to understand what triggers that BIOS hang.
- It probably is some bug that by chance doesn't trigger on windows.
+ The BIOS hangs due to a bug that windows doesn't trip over due to its ACPI noncompliance.
+ There is a reserved memory region called ACPI NVS, which belongs to BIOS and supposed 
+ to be saved/restored during suspend to disk.
+ However, Windows *against* the ACPI spec, saves/restores this region on suspend to ram too.
+ 
+ BIOS changes this region slightly on resume, and this change,
+  (more precisely a single byte change at <region start> + 0x29010 00->0xFF) 
+ makes it hang on  second resume. Since windows restores this region, this change is also restored and thus masks this bug.
+ 
+ Its likely that next version of linux kernel  will adopt same behavior.
+ 
+ Latest BIOS to have this bug is 1.42 (and updating to semi-
+ official(doesn't show up on all acer sites) 1.45 BIOS, was reported to
+ keep this bug)
+ 
  
  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...

-- 
Acer Aspire 5720 hangs on second resume from suspend, i.e. suspends only once [BIOS PROBLEM]
https://bugs.launchpad.net/bugs/160763
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.