Linux Kernel Developers Debate Priority-Based Shutdown Support

[phoronix]

Phoronix: Linux Kernel Developers Debate Priority-Based Shutdown Support

A Linux kernel mailing list discussion this holiday weekend that is seeing polarized views on the matter is around a new patch series proposed priority-based shutdown support for drivers/hardware...

https://www.phoronix.com/news/Linux-Priority-Based-Shutdown

[scottishduck]

I have to agree with gregg. If a piece of hardware is inclined to damage in an unplanned shutdown then surely the hardware itself should be changed to accommodate this.

[skeevy420]

This is the fault of listening to that bean counter with a slide rule and a spreadsheet who can't see beyond the next quarter and not an engineer who is looking ahead 10 years combined with shit happens and how if you don't design with shit happening in mind, that's on you when that shit inevitably happens. If you do both of those things you'll be in for a world of fuck me running in shit.

This is when redundancy and forethought are supposed to come into play and why you're supposed to argue back with the moron who wants you to use a MicroSD with Fat32 to save $1 a unit.

[elatllat]

Raid controllers have had batteries permitting safe shutdown for ages. there's no reason a ~$40k car can't have a <$1 RTC size battery as a UPS.

[yump]

Raid controllers have had batteries permitting safe shutdown for ages. there's no reason a ~$40k car can't have a <$1 RTC size battery as a UPS.

A potential problem: that battery has to tolerate temperatures between -20°C and 60°C, and survive for 20 years. Maybe a supercapacitor could do it. I don't know how robust they are.

[billyswong]

For the HW in question I have only 100ms time before power loss. By
doing it over use space some we will have even less time to react.

In fact, this is not a new requirement. It exist on different flavors of
automotive Linux for about 10 years. Linux in cars should be able to
handle voltage drops for example on ignition and so on. The only new thing is
the attempt to mainline it.

Regards,
Oleksij

Yeah, they squeeze the last drop of cost-cut, such that even car ignition may lead to voltage drop to the car computer.

[elatllat]

Also Odroid has managed to avoid damaging eMMCs for decades without any special software or batteries. Removable eMMCs on top of that.

[elatllat]

A potential problem: that battery has to tolerate temperatures between -20°C and 60°C, and survive for 20 years. Maybe a supercapacitor could do it. I don't know how robust they are.

The Tesla Model Y may be the best selling car this year and has no issues with its ridiculous number of batteries in any temperatures... of course it's not going to have power problems short of a car crash but then a bricked eMMC is the least of the worries.

[drhoho]

;Raid controllers have had batteries permitting safe shutdown for ages. there's no reason a ~$40k car can't have a <$1 RTC size battery as a UPS.

Except, they don't/won't.

Even BMW is too cheap/lazy to protect hardware despite extreme product margins. Battery voltage drops too low, blow the headlight, brakelight, window control module for a nice $1500 bill. Generate income for dealers...

Linux is supposed to crap the kernel to bailout greed.

[M@GOid]

Raid controllers have had batteries permitting safe shutdown for ages. there's no reason a ~$40k car can't have a <$1 RTC size battery as a UPS.

1 dollar more? Are you crazy? Those are people known to remove items in the next year model, in the hope consumers will not notice, just to increase profit margins.

You wouldn't believe the shit those people are capable off. Working at a dealer 20 years ago, I remember they changed the rubber cords of the trunk cover (in a hatchback model), to cheaper nylon strings, among another things. I swear engineers put slightly expensive stuff in the first year model, so bean counters can have something to cut in the subsequent years.