2.4 freezes on VIA KT133

2.4 freezes on VIA KT133

[Tomas Styblo]

Hi !

I've yet seen similar freeze reports here in the past, so I decided to post
my one too.
The said system is a server, Athlon 850, no overclocking, no overheating,
100 Mhz FSB, 512 MB brand RAM, Abit KT7A board with VIA KT133.

The system is heavy loaded in daytime, but almost idle at night. It crashes
only about three times per month. These freezes
started to happen after 2.2 -> 2.4 upgrade, that I performed early after the
2.4.1 revision was released. These crashes are completely untracable for me,
because there is nothing suspicious in the syslog afterwards. Also the
system runs ABSOLUTELY perfectly between the crashes  - no problems with
kernel compilations or similar tasks that push the system over stability.

The crashes occur absolutely unpredictably, sometimes even at night, when
the system is idle.

The system runs various network services and dynamic web applications that
use the MySQL database a lot. The only used filesystem is EXT2. I do not use
buggy redhat compiler.

This report is probably not very helpful, but it may be useful for those who
planned to purchase AMD / VIA solution for a server.
I am not subscribed to this list, but I will monitor it through a web
archive and will try to respond, if needed.

Thanks for your work !
Tomas Styblo

Re: 2.4 freezes on VIA KT133

[Mark Hahn]

> This report is probably not very helpful, but it may be useful for those who
> planned to purchase AMD / VIA solution for a server.

contrary to the implication here, I don't believe there is any *general*
problem with Linux/VIA/AMD stability.  there are well-known issues
with specific items (VIA 686b, for instance), but VIA/AMD hardware
is quite suitable for servers.

Re: 2.4 freezes on VIA KT133

[Albert D. Cahalan]

Mark Hahn writes:

> contrary to the implication here, I don't believe there is any *general*
> problem with Linux/VIA/AMD stability.  there are well-known issues
> with specific items (VIA 686b, for instance), but VIA/AMD hardware
> is quite suitable for servers.

VIA hardware is not suitable for anything until we _know_ the
truth about what is wrong. VIA is hiding something big.

Simple fix:

0. get lawyer
1. start class-action lawsuit
2. do discovery
3. unseal court records
4. done -- you may drop the case if not settled already

Well, something like that... not a lawyer, etc.
If you have the time and money, go for it. Have fun.

Creative Labs ought to toast VIA over blaming the sound card. :-)

Re: 2.4 freezes on VIA KT133

[Mark Hahn]

> > contrary to the implication here, I don't believe there is any *general*
> > problem with Linux/VIA/AMD stability.  there are well-known issues
...
> VIA hardware is not suitable for anything until we _know_ the
> truth about what is wrong. VIA is hiding something big.

this is INCORRECT: we know there are specific problems with certain
VIA hardware, but there is most definitely *NO* problem with other 
VIA hardware, which is eminently suitable for servers, workstations
and cabbage dicing controllers.

afaik, there are absolutely zero problems reported with kt133-no-a
machines, for instance.  mine has certainly worked flawlessly for a 
long time, on most every 2.3/2.4 kernel over the past year+.

Re: 2.4 freezes on VIA KT133

[Alan Cox]

> VIA hardware is not suitable for anything until we _know_ the
> truth about what is wrong. VIA is hiding something big.

I dont think thats true

> Creative Labs ought to toast VIA over blaming the sound card. :-)

Of course the card might be buggy too

The big problem with VIA is not that their hardware has bugs. Everyone has
bugs. I can get a problem with an intel chipset go to developer.intel.com and
generally get a straight answer and often a workaround. That makes me happy.
The problem isnt the bug, its not being given honest info on it.

If VIA had public errata that said things like 'Prefetch bursts can cause
problems unless you set bit 3 of blah' well we'd be able to evaluate the 
performance impacts and people could make sensible decisions and have 
reliable code.

Intel are not perfect either. We have a whole pile of laptops that crash when
speedstep triggers a trap we cannot handle. We have an APIC problem that took
much effort because they refused to help.

When vendors do help life gets a lot easier. AMD USB was a problem due to 
errata. Once they published the fixes AMD USB ceased to be a problem. 

Alan

Re: 2.4 freezes on VIA KT133

[Tomas Styblo]

It seems the problem is caused by some DMA related bug in the VIA chipset
and/or in the Linux DMA-IDE VIA driver.
I finnaly get rid of the freezes, by simply compiling the kernel completely
without IDE-DMA support. Now hdparm shows disks do not use DMA and
the system is stable, as far as I can say now.

I've tested it VERY intensely last couple of days and
did not manage to freeze it. For 12 hours a lot of concurrent processes
 copied gigs of data all over the disks, calculated
CPU intensive crypto etc, the system hasn't frozen. For debugging purposes
I also tried to downgrade to 2.2.19 with IDE-DMA activated.
It crashed. So it really seems DMA is the problem here.

Maybe I did not describe the freezes accurately in my first post. After the
freeze, the screen always went black,
and the system was dead - did not respond to pings, keyboard etc. It was
neccessary to hard reset it.

Tomas