Temporary freezes in AMD Sempron 2800+

Temporary freezes in AMD Sempron 2800+

[Ramkumar R]

Hi!

I have a laptop with an AMD Sempron 2800+ (Acer Aspire 3002NLC). The
machine seems to get unresponsive every time the frequency changes
(the music stops for a second, say)...I tested this by using the
ondemand kernel governor. I use linux-2.6.12-rc4-ck1 with the inotify
patch. (With two more modules, fuse and cdfs, but I guess that
wouldn't matter much). Watching the current frequency file in /sys
shows that this sudden freeze occurs whenever the value changes.

Thanx,
Ramkumar.

-- 
The day Microsoft makes something that doesn't suck
is probably the day they start making vacuum cleaners.
                                               -Ernst Jan Plugge

Re: Temporary freezes in AMD Sempron 2800+

[Michał Pytasz]

Hi,

On Monday 06 of June 2005 18:30, Ramkumar R wrote:
> I set the governor to userspace and tried echoing one of the speeds in
> scaling_available_frequencies to scaling_setspeed...it still hung for
> a second or two...just to ensure that, i did run `powernowd
> -vvvd`...everytime the speed changed to one of the valid frequencies,
> it hung...and one more observation, i've heard that amd supports quite
> a few frequencies...but scaling_available_frequencies just shows up
> 1600000 and 800000.
>
> and yes, i don't ACPI_CONTAINER in my kernel...
>
> Ramkumar.
>
> On 6/6/05, Micha³ Pytasz <mpytasz@pai.net.pl> wrote:
> > Hi,
> >
> > Dnia poniedzia³ek, 6 czerwca 2005 16:49, Ramkumar R napisa³:
> > > Hi!
> > >
> > > I have a laptop with an AMD Sempron 2800+ (Acer Aspire 3002NLC). The
> > > machine seems to get unresponsive every time the frequency changes
> > > (the music stops for a second, say)...I tested this by using the
> > > ondemand kernel governor. I use linux-2.6.12-rc4-ck1 with the inotify
> > > patch. (With two more modules, fuse and cdfs, but I guess that
> > > wouldn't matter much). Watching the current frequency file in /sys
> > > shows that this sudden freeze occurs whenever the value changes.
> > >
> > > Thanx,
> > > Ramkumar.
> >
> > 1. Did You try powernowd with userspace govenor?
> > I have similar laptop - Acer Aspire 1362 and had problems mentioned
> > below, it worked better that way.
> >
> > 2. Dou You have ACPI004,PNP0A05 and PNP0A06 Container Driver enabled ?
> > (if so disable it and retest) i had issues with this part, it's
> > "experimental" in power management->ACPI section of kernel config. (poth
> > with mobile sempron 2800 as well as desktop Athlon64
> >
> > Michal

Ok, 

Did You try if it works stable with Windows (scaling frequency) ? 
Maybe You have memory-related problems ?

Michal

Re: Temporary freezes in AMD Sempron 2800+

[Ramkumar R]

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On 6/6/05, Michał Pytasz <mpytasz@posejdon.wpk.p.lodz.pl> wrote:
> On Monday 06 of June 2005 19:21, Ramkumar R wrote:
> > no....i don't have (and don't want to install :) ) windows...do u mean
> > stuff like bit errors when u mean memory problems ? i just got this
> > laptop (about a month back)...and i had run memtest successfully when
> > i bought it...
> 
> Well, I've seen such a problem with athlon64 and faulty hynix module (probably
> You can find it in list archive). After I had it replaced everything became
> stable, memtest did pass with faulty module, too. Problem occured when cpu
> was going from low to high frequency.

mine hangs temporarily for *any* change in frequency though....

> That's why I asked about Windoze, I did not mean using it for work, but it may
> give a hint if it is a hardware problem. I don't think it could be a driver
> problem since I have similar machine with same CPU (Mobile Sempron 2800+, via
> k8n800) and it runs stable (with linux gentoo). I think it could be one of
> two problems:
> 1. Software: missconfigured kernel or misslinked libraries in the system (but
> in this case it should not hang hard and I guess there would be no
> correlation with frequency scaling)

i don't get that misslinked libraries part....please excuse my
ignorance but since the problem occurs even with the kernel level
ondemand governor, is this likely to be a problem...

> 2. Hardware problem.

just thinking that if it had been an hardware error, isn't it more
likely to be random rather than something which occurs repeatably when
the speed changes...i know only of memtest amongst hardware testing
utilities...if you know of any other utility which can probably help
me in this, please tell me.

> 
> If You wish, I could send You my kernel config.
> 

yeah sure, lets hope that helps :)

Ramkumar.

> Michal
> 

-- 
The day Microsoft makes something that doesn't suck
is probably the day they start making vacuum cleaners.
                                               -Ernst Jan Plugge

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Re: Temporary freezes in AMD Sempron 2800+

[Ramkumar R]

it worked at last! thanx a lot michal for your kernel config
file...the culprit was the ACPI Processor P-States driver
(X86_ACPI_CPUFREQ)....not that i need it (i dunno why i had it in the
first place :) )...but still, is this a bug ? (michal, may be if you
could confirm this by making it a module and loading it)...

yeah, one more question remains...does sempron have only 2 frequency
levels...that's what dmesg and the sys file seem to indicate....though
i've read that amd processors have quite a few speed levels (is that
only for the athlon series ?)

Ramkumar.
-- 
The day Microsoft makes something that doesn't suck
is probably the day they start making vacuum cleaners.
                                               -Ernst Jan Plugge

Re: Temporary freezes in AMD Sempron 2800+

[Ramkumar R]

well...i guess i was a bit hasty...the p-states driver was not the
problem...rather, a more interesting pattern has come up...it seems
that the freeze occurs whenever i am on a X display (i.e. it isn't
even a problem when i have X running and i am in one of the
tty's)...in fact, to confirm my doubts, I set up my .Xsession to
simply loop, sleeping for a second, and toggling between the two
frequencies. It freezes when i am on the X display, and the problem
disappears the moment i do a alt+f1...this is really strange...

Ramkumar.
-- 
The day Microsoft makes something that doesn't suck
is probably the day they start making vacuum cleaners.
                                               -Ernst Jan Plugge

RE: Temporary freezes in AMD Sempron 2800+

[Langsdorf, Mark]

> yeah, one more question remains...does sempron have only 2 
> frequency levels...that's what dmesg and the sys file seem to 
> indicate....though i've read that amd processors have quite a 
> few speed levels (is that only for the athlon series ?)

The powernow driver reads the data provided from the BIOS.
If the BIOS provides an incorrect number of pstates, the
driver has no way of knowing that there are other states.

How many pstates you have is determined by the frequency of
the processor.  A Sempron 2800+ is a 1.6 GHz processor and
should only have 2 pstates - high and low.  It looks like
your system is set up correctly.

-Mark Langsdorf
AMD, Inc.

RE: Temporary freezes in AMD Sempron 2800+

[Langsdorf, Mark]

> well...i guess i was a bit hasty...the p-states driver was 
> not the problem...rather, a more interesting pattern has come 
> up...it seems that the freeze occurs whenever i am on a X 
> display (i.e. it isn't even a problem when i have X running 
> and i am in one of the tty's)...in fact, to confirm my 
> doubts, I set up my .Xsession to simply loop, sleeping for a 
> second, and toggling between the two frequencies. It freezes 
> when i am on the X display, and the problem disappears the 
> moment i do a alt+f1...this is really strange...

Sounds like a potential motherboard issue.  Some low-end
motherboards don't have large enough PCI data buffers to
store all the way through a pstate transition.  There's 
not a lot I can do about it.

-Mark Langsdorf
AMD, Inc.