Linux kernel boot process

[Sannu K]

On Sat, Aug 4, 2012 at 9:04 PM, Kristof Provost <kristof at sigsegv.be> wrote:
> On 2012-08-04 20:53:00 (+0530), Sannu K <sannumail4foss at gmail.com> wrote:
>> I had a doubt for long regarding hibernation. It takes a very long
>> time to resume from hibernation in Linux compared to windows.
>>
> I don't actually have a windows machine to compare. It's quite possible
> that this is true, but I can't say why it'd be the case.

Is it possible to determine the reason for more time in hibernation
compared to windows (or profile the resume time)? If possible I could
do it in my machine and get some info which may be useful. Some one
may jump to solve this (or there may be some magic tweak to get a
better resume time) once it is profiled.

>> Why should all the drivers be started again? Just we can load
>> the disk driver and some essential part of the kernel, disk driver (or
>> only few drivers necessary for reading the hibernate image) and use
>> the drivers stored in the disk (from hibernation image) for rest of
>> the devices.
> When resuming from hibernation all devices were powered down. The kernel
> needs to run through all of the initialisation code again. It needs to
> upload firmware, set configuration registers, ...

That makes sense. Does that mean during hibernation the state of
drivers will not be preserved? Will the driver code be discarded
without saving in hibernation image (as we are starting the driver
again while resuming)?

Thanks,
Sannu K

> Regards,
> Kristof
>