Ubuntu 11.10 hibernate still consume battery

Report a bug is all I can suggest

Are you sure the laptop is hibernating? If the swap partition is not big enough, then the computer will not be able to hibernate.

Also, people get a little confused with the difference between 'suspend' and 'hibernate'.

In suspend, most of the hardware is powered down and only a small amount of power is used to sustain the memory, which is kept alive. Normally, the computer will indicate it is in suspend mode by flashing the power LED every second or two. This is the only way you can tell the computer is in suspend mode. Suspend mode still consumes battery power as it has to pulse the memory bus many times a second to keep the memory alive. The ability to use suspend mode is mainly provided by the Hardware and BIOS, however the operating system must be able to re-initialise hardware such as network cards and video cards for the resume to be successful.

In hibernation the memory gets written to the swap partition, after which _all_ of the hardware is powered down. Absolutely no power can or will be used while the computer is in hibernation - it can stay in this state indefinitely. There is no visible confirmation that the computer is in hibernation, since it is completely powered down. When the machine is powered back on it will go through post as normal, and will then have to load the memory contents out of the swap partition. For this reason a resume from hibernate is mostly a software, and specifically an OS problem, although again the OS must be able re-initialise the hardware successfully.

If you think the computer is in hibernation but the power LED (or other) is flashing, then most likely you are in suspend mode.

Chris

Thanks Chris, my swap partition should be big enough, and there is no light flashing during "hibernate". However, there is something strange, when the lip is opened, the system automatically resume from hibernate, while the resume process is supposed to trigger by pressing power button. Also, the resume process take much longer than suspend resume. I am pretty sure the system goes hibernate rather than suspend, as it has alot of disk read write before power off, just suspect that some hardware cannot be power off due to driver or config issue. Is there any config file or log to check the hibernate process is doing properly?

Thanks.

That's rather strange. Check your BIOS as some have settings for events that will trigger power on/resume such as a keypress or opening the lid. Presumeably they have to consume some power for this, though it should be a very small ammount indeed.

Hibernate should power down the machine completely - problems with driver modules being incompatible normally show up when the hardware fails after the resume, for example a video card or network card that doesn't re-initalise properly.

Chris