Re: Laptop shock detection and harddisk protection

From: Greg KH
Date: Fri Sep 12 2008 - 15:09:42 EST

On Fri, Sep 12, 2008 at 01:35:54AM +0200, Tejun Heo wrote:
> Shem Multinymous wrote:
> >> That reduction comes because input device supports poll and
> >> sysfs_notify_event() does about the same thing. The uesrland daemon
> >> can just poll on a node and read data nodes when poll event on the
> >> node triggeres.
> >
> > Agreed.
> > There's another issue with the current sysfs interface, though: hdapsd
> > needs to read (x,y,timestamp) tuples, whereas sysfs provides just x
> > and y in separate attributes which cannot be read atomically together.
> > We can add a sysfs file with "x y timestamp" readouts, though this is
> > unusual for sysfs (and certainly incompatible with hwmon).
> Yes, right. Forgot about the atomicity part altogether. Thanks for
> bringing it up.
> >> Unloading heads will be simple. Just echoing timeout in ms to sysfs
> >> nodes, so I don't think it's a good idea to push out actual unloading
> >> to another process especially as fork doesn't inherit mlockall.
> >
> > I had in mind another daemon listening for "unload now" events, so no
> > forking needed.
> > This second daemon might make sense if we push the logic of deciding
> > *which* disks to unload into userspace, since this logic is the same
> > for the ThinkPad style and the HP style.
> Hmmm... I can't (yet) see the benefit of having two separate userland
> daemons.
> >> On a related note, is there any plan to merge tp_smapi to mainline?
> >> It seems you put a lot of work into it and I don't really see why it
> >> should stay out of tree.
> >
> > The only issue I'm aware of is finding a reasonably-named maintainer.
> > On the technical side, the reviews on my lkml submission of
> > thinkpad_ec+hdaps seemed good and all technical comments are since
> > addressed. The code has been stable, well-tested and packaged by major
> > distros for years.
> Cool, can you please post the patch to the lkml and cc Greg
> Kroah-Hartman <gregkh@xxxxxxx>, Andrew Morton
> <akpm@xxxxxxxxxxxxxxxxxxxx> and me?

Sorry, but no, I can't accept this code as it is coming from a "known
anonymous" person containing information that it is not known where it
came from.

We went over this before a number of years ago, that's why this code
isn't in mainline :(

In short, "Signed-off-by:" from people who are known to be anonymous is
not allowed.


greg k-h
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