Re: [gentoo-user] Kernel freezes

[Alexander Puchmayr <alexander.puchmayr@linznet.at>]

Am Samstag 06 Juni 2009 schrieb Volker Armin Hemmann:

> *sigh* Ok, just for starters - all AMD cpus of the Athlon64 architecture
> have a builtin agpgart. This agpgart functions also as an iommu. This is
> a great hack to have a hardware iommu . Intel does not have this, so they
> rely on software. The solution came up while AMD devs and linux kernel
> devs worked together.
> Please read the following links:
>
> http://en.wikipedia.org/wiki/Iommu
>
> http://marc.info/?l=linux-kernel&m=107759901509280&w=2
>
> http://marc.info/?l=linux-kernel&m=107764033904042&w=2
>
> the iommu is needed so 32bit pci devices can live with their pci adress
> space behind 4gb and other sweet things.
>
> Sadly the iommu needs a minimum on memory for itself - and uses the agp-
> aperture. This is fine, but mobo vendors suck and make it too small/or
> not available. In that case the kernel is forced to use real memory for
> the iommu.
>
> In short, that message has nothing to do with your problem.
>
Thanks for these informative links

> The NR_CPU message is confusing - I strongly suspect that your kernel
> config is really fucked uo.

?? As I have a DualCore-Cpu, I changed NR_CPU to 2, something wrong with 
that? What else can be fucked up? I Enabled Multi-core scheduler 
(hyperthread is disabled)

>
> Please enable:
>
>  [] Check for low memory corruption
>  [] Reserve low 64K of RAM on AMI/Phoenix BIOSen
>
> in the kernel config. Also clean it up and remove stuff like
> 'hyperthreading scheduler'.
>
Already done.

> If the problem persists, start testing your hardware.
>
How? I don't have access to special test equipment to test hardware. This is 
the only AM2(+) board and the only AM2 CPU I have. The RAM is also unique 
to this machine. 

> I would suspect the PSU.

The Powersupply? What makes you think that the PSU can be the cause of a 
system crash? 

Greetings
	Alex