On 2020/06/29 3:23, Simon Arlott wrote: > On 19/06/2020 00:31, Damien Le Moal wrote: >> On 2020/06/18 21:26, Simon Arlott wrote: >>> I haven't verified it, but the BIOS leaves the power off for several >>> seconds which should be long enough for the HDDs to spin down. >>> >>> I'm less concerned about those suddenly losing power but it would be >>> nice to have a stop command sent to them too. >> >> OK. So maybe the patch should be as simple as changing SYSTEM_RESTART state to >> SYSTEM_POWER_OFF if reboot=p is set, no ? Since that is consistent with the fact >> that reboot=p will cause power to go off, exactly the same as a regular >> shutdown, it seems cleaner and safer to use SYSTEM_POWER_OFF for the entire >> system, not just scsi disks. > > That could be a bit misleading because the power isn't going to stay > off. Some of the network drivers have specific WOL behaviour changes > for a power off. The point is that the power goes off, same as for a SYSTEM_POWER_OFF shutdown. It do not think it matters how long it will be off before your BIOS restarts the laptop power. And actually enabling the NICs WOL function would I think actually be a very good thing: if the PSU power cycling fails, the machine can still be remotely woken-up as configured by the user. > Power cycling the PSU is not something that every BIOS will do, so it's > not that simple. It could be a module parameter but I'd be concerned > that some other code will assuming the system should be powered off and > all of my reboots will become power off events. Or define a SYSTEM_RESTART_P that essentially does what SYSTEM_POWER_OFF does + the addition of telling the BIOS to restart the PSU, if the machines supports it. What happens if one does a reboot=p on a machine that does not support it ? Does this become a shutdown, or does it become a normal reset ? -- Damien Le Moal Western Digital Research
