Best posts made by c4c

@george1421 That’s literally perfect, thanks! Seems fairly straightforward, I’ll update this thread with progress later.

As a note, we are charity refurbishing computers/laptops and donating them on. We have our own external database that we push data to but we use FOG to harvest data (we’ve created our own inventory and registration scripts to record all drives and pci devices and every RAM module separately). We also use FOG to image outgoing devices and to load tools like parted magic. We are now writing our own data erasure and verification script which is why we need to be able to sleep machines (in order to unfreeze drives), this will be used to effectively complete the automation of processing incoming items, currently we have to use external tools to perform data erasure and some of these we have configured to also report into our database but it would be quicker/more convenient to be able to do it all through 1 boot of the machine, hence adding the functionality to our FOS image.

@george1421 We’re half a step ahead here! Already enabled all the CONFIG_ACPI options and CONFIG_SUSPEND etc. and built a new kernel. We also enabled RTC for rtcwake but that still leaves the screen blank. It also turns out that acpitools (something we thought might work) tries to suspend using /proc/acpi/sleep which, from what I have read, is deprecated because it’s an abuse of /proc.

We are running under the assumption that at least some power management tools have scripts built in to reinitialise monitors/displays etc. using methods which are currently unknown to us and that the easiest solution would be to just get one of them to do it all for us. Unfortunately, so far, this hasn’t worked out.

Right now I’m thinking we need to see if we can just tell stuff to turn back on so I might have to figure out enough ASL to turn the screen back on using acpiexec and an AML file. I’ve also added kexec in to our init though so maybe we can just reload the init after sleeping to unfreeze and that will restart everything.

Another option might be (if this is possible) to use ASL/AML/acpiexec to directly remove power from the drive and then power it back up.

hdparm has an unfreeze command (doesn’t always work) but unfortunately nvme-cli has no equivalent, even tried setting the power states to their lowest possible and then setting them back, also tried the reset command (didn’t work) and the reset-subsystem command just made the drive disappear.

In general, in buildroot, I can’t find any power management tools other than the acpi stuff and powertop (which is useless). Another option might be to try and add in uswsusp manually but the last build of that is from 2011!

The amount of stuff we are learning to solve one, small problem is nuts.

Final update: Got everything working! The monitor not waking up after sleep was fixed by adding in some extra graphics drivers to the kernel and we’ve found some solutions to wiping difficult machines (like Lenovo’s) which normally force you to use tools built into the UEFI or a special Lenovo wipe program that only works on certain models and asks you to confirm 5 times and gives you a random generated key that you have to enter in after a reboot. As a note, even parted magic fails to wipe Lenovo drives.

Anyway, thank you @george1421 you’ve helped me to learn a great deal and enabled our success in this.