Comment # 43 on bug 918158 from Ivan Topolsky

> > RAM corruption is thus very unlikely
> It becomes more and more likely ...

I still don't buy dammage RAM sticks, as I've tried again memtest86+ for
extended periods of time and still no reported problem.

I'll side with Thomas on that one.

> The question is: do you have any optimization around, that is e.g. preloaded
> libraries (echo $LD_LIBRARY_PATH $LD_PRELOAD) for the used CPU/chipset
> and/or selfcompiled and/or third party kernel,

No, the installation is stock.
I use my laptop in production and thus haven't optimized much.

> third party modules

*That* is what I've been thinking too.

Two third party modules :

- Nvidia closed source kernel driver.
And unlike their good reputation on laptops, Nvidia binary on laptops are
usually very problematic. (All the laptops I've been through display random
texture corruption, problems text-mode console as they don't do KMS, etc. it's
far from being specific to that laptop. Seems more likely that Nvidia
concentrates their effort at supporting Desktop/Workstation on Linux and
neglect laptops, see the debacle around Optimus)

As Nvidia has moved to G04 and excluded my chip from that set, I've switched to
opensource Nouveau driver.
All the segfaults that happen here and there happen AFTER this switch.
(Although I don't have texture corruption anymore. The only problem I have is
that the very specific kernel version that opensuse uses, the 3.16 has a bug
that prevents nouveau from completely shutting down the backlight when putting
the screen in DPMS OFF)

- WL restricted source driver for the broadcom WiFi b/g/N mini-PCIe card
built-in by Dell.
That's what opensuse installed by default back when I acquired this laptop.
Back then I tried experimenting with alternative, but b43 was reverse
engineered and was missing a lot of feature, and the brdcmsmac opensource
driver was too new, and had speed problems (missing 5Ghz, speed droping to
10mbits on 2.5Ghz N).

I've noticed in the logs that the wl driver makes the kernel spit messages.

As nowadays brcmsmac seems to be in much better shape (only power saving, AP
mode and some special channel mode are missing- N is fully functionning,
including at 5Ghz), I'll try switching and see if the machine becomes stabler.

That's also the main difference between this problematic laptop (has BCM
wireless) and the older laptops (external Wifi PC-CARD that I plug when I
actually need it) and other destkop/Workstations I use (no Wifi).

> Also which modules are unloaded before hibernate/suspend and reload
> afterwards if any ?

I there a cannonical way to list them ?

I would suspect the USB drivers.
Currently, the bluetooth (BCM5880) is wired over USB in the laptop, and I have
a USB-using microSD reader mini card.

They use stock kernel drivers.



Also, last but not least: ACPI is of course also 3rd party (byte) code running
here.
Not sure if I can do anything about that one (BIOS/Firmware from Dell is
up-to-date).


I'll see what I can do. If the segfaults disappear, It might have been the BCM
restricted source driver sliently corrupting the rest.