Installing powerd on earlier F11 builds

[Paul Fox]

sridhar wrote:
 > We're still grappling with the aftermath of http://dev.laptop.org/ticket/10402
 > 
 > XO-1.5s that have been damaged from overheating are being replaced,
 > but we also need a means to prevent others from meeting a similar
 > fate.
 > 
 > Our preferred solution is to upgrade to our latest build, which has a
 > fixed powerd. However, we are finding that many teachers are unable to
 > do this (due to lack of time, etc.). For them, we are devising a
 > simple means for them to specifically update powerd on their systems.
 > This method employs a modified customisation stick[0][1] to
 > automatically install the RPMs.
 > 
 > A challenge is that the XOs came from the factory (starting in May
 > 2010) with a range of builds ranging from os65 to os203. The earlier
 > builds have power management handled by ohm[2] instead of powerd. This
 > raises some questions:
 > 
 >   1. are there any problems with simply removing ohm and installing powerd?

very old versions of powerd will certainly work fine, and more recent
ones may too.  for the most part powerd checks for the existence of
features (e.g., nodes in /sys) before using them.  however, some of
those features (e.g., the lid-state node) are part of the solution to
this unwanted wake-on-lid issue you're having.

 >   2. at what point did powerd become usable in F11 XO builds?

i'm not sure what you're asking here.  powerd was usable on F11 long
before it was able to suppress wake-on-open behavior.  powerd-29
fixed that in 10.1.3 (#10403)) for 1.5 laptops, but XO-1 required
kernel support.  XO-1 started doing the right thing with powerd-30
(#10424), but that required kernel fixes for lid state detection and
wakeups (ad366d03315d1bd461db24f68a7506fff5f48a1e and 
1edf204d38125e46ae9e45c641f9b7877eec2a5c)

 >   3. are there any other changes that we need to be aware of, e.g. in
 > the power management panel in My Settings in Sugar?

yes -- i think releases built with ohmd won't have the sugar control
panel smarts to control powerd's behavior.

 >   4. do we need to upgrade the firmware as well?

i really don't recall.  sorry.

 >   5. is there anything else that we need to be aware of?

as you've gathered, there are a lot of pieces that make all this
work:  the UI, powerd, the kernel, the firmware.  if you could upgrade
all of the last three, you might be fine, but of course then other
interactions between your user-level and the kernel might get upset.

paul
=---------------------
 paul fox, pgf at laptop.org