power management [LWN.net]

power management

Posted Apr 12, 2007 16:04 UTC (Thu) by nhippi (subscriber, #34640)
In reply to: Two examples of abandoned hardware by dufkaf
Parent article: Two examples of abandoned hardware

> You even cannot read root device name (settable via flasher) early in boot sequence without dsme already running

That's just a line in a shell script that asks from dsme for the "root" device.

> Or you mean I should ignore bme binary and have it running (in otherwise free system) for the charging to work?

That's my impression. Notice that I don't have anything to do with bme.

> Do you also suggest I should leave whole uclibc based initfs partition (mostly with closed stuff) also in place just because of bme in it (probably linked to that uclibc and other proprietary stuff)?

Once you have a otherwise free system, you could ask for a static bme binary. That would be a request much harder to to argue as not reasonable, than the "plz provide commercial quality images for old hardware forever" request.

> Well, everything is solvable but telling me this is a myth and there is no problem because everything is in kernel is simply not true.

I guess we disagree in terminology. I consider power management to be the code that enables powering down unneeded devices, dyntick, managing the power states the core etc. Wikipedia kinda agrees. I guess your idea of power management includes battery charging logic. Which is fair enough, related to electric power.

But I already told in my first post that bme is the hard bit.

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power management

Posted Apr 12, 2007 16:58 UTC (Thu) by dufkaf (subscriber, #10358) [Link]

"That's just a line in a shell script that asks from dsme for the "root" device."

Not sure what you mean, there is cal-tool command in initfs which can read root device name stored in config partition (cal-tool -r), this does not work without dsme running because cal-tool does it via closed libraries (libcal,libdsme) in /usr/lib (in initfs) which need dsme to be running. It looks like dsme proxies all access to config partition and libcal or libdsme communicates with dsme over socket in /tmp to do the dirty work. So you cannot read stuff from config partition without having dsme running. I guess there is lot of interesting stuff stored in config parition (like WLAN MAC address?) so you probably need dsme (and whole initfs partition with other binaries) also for wlan initialization at least. I'm not sure if you can kill it then without trigering watchdog, maybe yes, maybe no. Also the config partition might be needed for bootloader too so you probably need to leave it as is too.

Even without power management stuff (no matter what is the definition) it is not easy at all to roll your own free solution for n770 and do not lose basic device functionality. Free kernel is not enough. And wasting a lot of time figuring out how the closed stuff works with real possibility that sometime in future you hit some stone wall and all your effort is wasted is not funny.

"Once you have a otherwise free system, you could ask for a static bme binary."

You must be joking. Yes, I can ask, will I get it? Will it work and solve all problems? Maybe. Maybe not.

Anyway, this should better go to maemo-developers, not here.

power management

Posted Apr 12, 2007 17:12 UTC (Thu) by mrfredsmoothie (subscriber, #3100) [Link]

Yeah, especially considering the device wasn't "commercial quality" for at least months after it was released.

Please. This "commercial quality" thing is a total canard. There are quite a number of flagship FOSS projects producing software of a quality no commercial product can match, and you well know it, or you wouldn't even be reading this site.

The fact is, given enough information -- or lacking that, time and people who live in jurisdictions where EULA restrictions against reverse engineering aren't enforceable -- the community can, and probably will produce images for the N770 of a higher quality than that which shipped on the device when it first became available. Nokia could certainly help with that, but it seems their policy is to be officially unhelpful and maybe turning a blind eye to occasional, sufficiently cryptic attempts by some of their employees to offer bits of help.