Run OFW heat spreader test
quozl at laptop.org
Mon Jan 23 01:58:29 EST 2012
On Mon, Jan 23, 2012 at 05:32:05PM +1100, Sridhar Dhanapalan wrote:
> On 23 January 2012 17:20, James Cameron <quozl at laptop.org> wrote:
> > I thought you were doing this test to detect early units that may have
> > a failed heat spreader, and you were doing it at the time of reflashing
> > because that's when you had some control.
> Yes, that's the primary reason. Our initial batch of XO-1.5s have an
> inefficient heat spreader. They've been burning out, and replacing the
> motherboards is getting expensive and time consuming. We'd like to
> detect potentially faulty units early, and recommend a heat spreader
> change for them.
I don't think burning out is the right wording. Perhaps you mean they
have been losing contact with the CPU.
This would be a gradual process, and would be encouraged mostly by
handling, including compression of the case and opening and closing the
lid. I'm certain fs-update would not affect this process.
> As a thought - maybe we should be identifying the serial number as
Yes, you should be able to skip the test if the serial number is not in
the range of your initial batch of XO-1.5s.
> > I don't think it is worth doing this test for the purposes of flashing
> > the XOs. ?The built in throttling will work fine. ?If the heat spreader
> > is dodgy, you'll either get a hang during fs-update or it will take much
> > longer.
> Hangs are annoying and don't provide any useful feedback to the user.
> It might be true that the XO can't get damaged from flashing, but the
> symptoms at runtime are random and are difficult to diagnose. I think
> that forcing a heat spreader test can provide a warning to the user
> and allow them to do something before any damage or annoying behaviour
> can begin.
We have long since fixed the problem that led to random symptoms after
boot following an incomplete reflash ... I trust you are using that code
which writes the zero block last in the .zd file? So unlike your
previous experience I don't expect any random and difficult to diagnose
symptoms. Perhaps you should test what the result is. The unit should
fail to boot. You can simulate a hang during fs-update by forcing the
power off. The result should be identical.
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