Hi, I'm wondering - is there a way/interface that I could use to notify the Linux kernel that the power is about to go down? I'm thinking about SD cards in particular and how to make them more immune to unexpected power loss, and I've found that some SD cards support something like "mmc_poweroff_notify", which is called in the mmc_suspend function. Assuming that I have the information about upcoming power loss (provided by e.g. external interrupt, PSU voltage monitoring etc) how should I pass this information to the Kernel so that it will try to clean up resources - in particular MMC subsystem? Let me show some background - we have a SoM which has a lot of components. On the SoM we have a PSU which operates on 24V voltage. We would like to monitor the PSU's voltage and when we detect that the voltage has dropped from 24V to 12V this is highly likely an unexpected power loss/cut, therefore we would like to inform the Kernel (in particular mmc subsystem) that the power loss is coming. I can imagine something like this - we have a driver that does voltage measurements or waits for an external interrupt (triggered when PSU's voltage drops from 24V to 12V) and then calls some functions that will allow the Kernel to do some cleanups, but the question is what are these functions? Are there any? BR Patryk
