Best way to debug an Intel Core i5 hang - likely graphics (possibly power) related

[Graeme Russ]

Back again ;)

On 01/22/2012 04:40 AM, Mulyadi Santosa wrote:
> Hi again :)
> 
> On Sat, Jan 21, 2012 at 16:58, Graeme Russ <graeme.russ at gmail.com> wrote:
>> Tell me about it :( - I've been here before, just not with the Linux kernel
> 
> 
> At least I can tell you will get hiccup less :) Anyway, you do have
> data backup, right? Just in case it causes corrupt and you lose some
> of your data. Better safe than sorry...

I have /home and a separate HDD :)

>> I got netconsole working and it took a while to crash, but it finally did
>> and guess what - No oops :(
> 
> Ok, no luck....how about serial console? same result? (I am not sure
> which one will be helpful in your case).

Haven't tried serial console - not convinced it will help (see below)

> Just crossing my mind, is this bug also happen if you work strictly in
> text console i.e no X Window at all?
> 
>> I've added more (see attached config)
> 
>>From what I can see at a glance, you already enabled enough debugging
> features....so just keep it that way at least for now.
> 
>> Also, I am using a very recent tip of linus' branch (commit
>> ccb19d263fd1c9e34948e2158c53eacbff369344)
> 
> I think this is the way it will go, you would likely doing bisecting.
> Thing is, you first need to find kernel version that works well. You
> said you have trouble with 3.1.9-fc...how about 3.1.8 or below?
> 
>> Hmmm, any way to test this theory?
> 
> Let's say, switching cpu governor? What do you use now? ondemand? then
> try to switch to conservative. Or just lock the cpu frequency into
> certain number.

I managed to make the system more unstable as I trimmed the kernel and
added debugging info. The symptoms were slightly different (graphic freezes
rather than flashing screen)

To isolate i915, I've installed a nVidia 8600GT from my old machine. Even
though I blacklisted i915, it still loads, so I've done an 'rmmod i915' to
force it out.

So far it all seems pretty stable - I'll leave it powered on for a few days
to make sure. I'm then going to buy an ATI 5450 (cheap and passively
cooled) and see how that goes.

After a week of uptime, I'll switch back to the i915 driver and see what
happens. If I get a hang, I'll get the i915 maintainer on board with my problem

I think the lack of any kernel messages is due to a hardware conflict which
hard-locks the machine. Even the reset button does not respond.

Regards,

Graeme