[maemo-developers] [maemo-developers] RE: defective memory?

[From: Siarhei Siamashka]

On Wednesday 20 September 2006 01:12, Olivier ROLAND wrote:

> If your device is broken then mine is also.
> I don't think at all that we speak about (small) fraction because
> majority of users won't even notice the problem.
> My device seem stable until I stressed it. And stressed it is not a
> "condition suffisante" to make the problem happen.

That's exactly the point. The device is quite usable and most users will not
detect any difference on most common operations. It is a very good sign as 
looks like in order to get rock solid stability, we only need to allocate and
lock the problematic memory page early at boot time and do not let any 
applications use it.

> When I have time, I will make extensive test on my device to check
> exactly when the problem occur.

Please do it, now with the lastest version of the tester and 40MB tested
block, the coverage is almost 2/3 of physical memory. If that's a certain
location in memory, the chances that it can be easily detected are quite 
high. Please verify that the offset of faulty address within 1KB page is
reported to be always the same between different runs (it is equal to 1a5 
for me).

I'm trying to find a way to get a full physical address of that page. In my
last tests I managed to mmap '/dev/mem' (just using 'read' function
segfaults), but did not have enough time to experiment with it much yet.

> My doubt about "small fraction" are probably driven by the fact that I
> was "hit" by 'white screen of death' 4 weeks after buying the device.
> So I guess that during the reparation my 770 was checked (again) by the
> conventional Nokia diagnostic.
> I conclude that the conventional Nokia diagnostic doesn't detect the
> problem.
>
> To make things clear, I don't want to make negative publicity at all. I
> enjoy this device a lot and I've ported Streamtuner on it with lot of
> great feedback from users.
>
> My 2 cents.

I don't want to make negative publicity either.  My only goal now is to find
some reliable technical solution for both diagnostics and workaround of such
problems. After all, I have a good motivation for that :)

I'm grateful to Nokia as they are also trying to investigate the problem. I'm 
quite confident that we can come up with some solution, and it will have 
some positive effect for Nokia 770 community as a result. This is a new
device, software and tools for it are still being developed. We are all
learning and getting more experience.

> PS: I don't know what is "the conventional Nokia diagnostic" but as far
> as I know there is always a "conventional XXX diagnostic" in reparation
> centers.

By the way, when looking for additional information I found some Sharp
Zaurus community forum and asked what they use for hardware diagnostics 
in the hope that I could use the same tools. Somebody replied me that 
hardware diagnostics tools are built in Zaurus firmware and are accessible
from boot menu.