Re: Disable FastBoot

MikeS <[email protected]> wrote:

> On 17/11/2025 12:26, VanguardLH wrote:
>> "Carlos E.R." <[email protected]> wrote:
>> 
>>> On 2025-11-16 03:18, VanguardLH wrote:
>>>> Anssi Saari <[email protected]> wrote:
>>>>
>>>>> Dan Purgert <[email protected]> writes:
>>>>>
>>>>>> Win10, 11 have that "FastBoot" thing that mucks with hardware releases
>>>>>> on "reboot" (win basically goes into hibernate).
>>>>>
>>>>> No. Reboot is always reboot, Windows would be completely useless without
>>>>> that. "FastBoot" aka fast startup happens when shutting down if not
>>>>> disabled. And it's hibernate without hibernating apps so fairly useless.
>>>>
>>>> Actually Fast Starup is a full hibernate (all memory copied into the
>>>> hyberfil.sys file).  The computer then goes into sleep mode.  When
>>>> brought out of sleep, the computer resumes from sleep.  If, however, the
>>>> computer ever lost power during sleep, the computer resumes using the
>>>> hibernate file.  Because a memory image is reinstated or resumed from a
>>>> Fast Startup mode, there is no re-initialization of hardware.  This is
>>>> the same as a Windows restart which is a warm boot.
>>>
>>> No, hardware has to be reinitialized "somehow". Hardware has been
>>> powered off, they have to be put back in the same status as they were
>>> when the machine hibernated. The driver needs adequate entries to
>>> restore status.
>> 
>> It is the lack of initialization of hardware on a FastBoot startup why
>> hardware that was hung, or in an inoperable state, remains so.  FastBoot
>> copies a memory image of the kernel and drivers in their state at that
>> time, and restore those states on startup.  Even if the hardware gets
>> the CPU reset on a cold boot, FastBoot is going to reinstate its memory
>> image of the kernel and drivers.  The kernel and drivers are NOT loaded
>> on a FastBoot.  They are resumed from a saved state.  That the memory
>> image of states doesn't match hardware state is why FastBoot causes
>> problems.  When rebooting to attempt troubleshooting, FastBoot can make
>> the boot-time menu disappear so fast the user has no chance of hitting a
>> key to get it recognized to go into troubleshooting mode, or make a
>> selection from a boot menu.
> 
> A little knowledge is a dangerous thing. Here is an accurate description:
> https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/distinguishing-fast-startup-from-wake-from-hibernation

"2. Next, the power manager sends system power IRPs to device drivers to 
    tell them to prepare their devices to enter hibernation."
    
You've never encountered drivers that did not restore state correctly on
resuming from hybrid hibernate?

"If the driver for a device configures the device differently depending
on whether a cold startup or a wake-from-hibernation occurred, this
driver should, after a fast startup, configure the device as though a
cold startup occurred."

Those wonderful "shoulds".  

If there is a power outage during sleep, or during a Windows session,
how is all this graceful recovery information going to be captured on a
computer that is instantly dead?