UnSolved - Laptop Freezes

I am very curious what is C-state stepping. I looked at the pdf, but really could not make anything out.

[Saist]

okay... If you don't know a lot about electrical design, or how a processor drops power, this could be a bit difficult to explain...

Give me a few minutes to put something together.

[Saist]

Alright, I feel a little cheap doing this, but two separate posts so I can fit all the images.

These are taken from page 81 of the PDF linked earlier, and are the power specifications for a Socket 754 Turion Processor from AMD.

Our first state is the maximum performance state. This processor has a top speed of 1.8ghz, and we can see our voltages assigned to drive the processor. We can also see that this processer's thermal envelope is set at only 24watts.




However, in order to save on heat, power, and battery life, this processor supports downclocking, which decreases the speed and voltage. This specific processor will first downclock to 1.6ghz, and we can see that the voltages have dropped, as well as the Thermal Envelope.




Most AMD processors with downclocking enabled will have the minimum state of 800mhz... not coincidentally linked to the 800mhz Hypertransport bus the AMD processors are fed from. We can also see that at 800mhz our thermal output is more than halved to less than 8watts. Our voltages have also gone way down as well.




Next post, I'll go over the C-states.

[Saist]

Below the minimum speed is a halt state, basically the first of the suspension states. When the processor has no information to process, it will sometimes drop into the Halt-state. This is actually a known issue on Intel's Prescott processors which are known for dropping down to a halt or C state in order to cool off.

In this state the Athlon64 processor is technically still on, with 2.2watts still sending and receiving data.






Then we get to the real C-states. The halting of the processor. The power is dropping all the way down... almost a complete shut off.




And we go lower... less power...




Till we hit S3, the suspension mode.





Alright, now, what your problem sounds like, and again, I've only seen this on Prescott processors, is that it is dropping to a lower power state, probably hitting Halt or C3, and not coming back out of it properly.

As to what could be causing the problem... I don't know. Technically, ATi's admittedly weak PowerPlay for Linux shouldn't be affecting the Halt/C state of the processor. However, given what I know of the existing chipset drivers for ATi's products, something could possibly be screwy depending on how the vendor sets voltage controls. (e.g., MSI completely skimping out on Voltage controls on Radeon Xpress motherboards).

On the other hand, it could very well be a problem with the BIOS itself, or how the vendor (in this case) Gateway, has the system setup and again, what the voltage control signals are.

The only realistic solution I could give is to contact Gateway and ask if there are any known issues with power states on that laptop... however I doubt they would be able to answer the question.


oh, yeah duh, forgot this part: As to why it would work properly with music playing? Reason why I think it's a voltage control / Halt/C state problem. As long as the processor is being fed information, any information, it won't downclock itself.

Playing the music prevents the system from downclocking or hitting a halt state. Unlike the Prescott, the Turion64 isn't hot enough to be going into Halt to cool off.

Now, I could be off about what's going on... but I'm not coming up with a whole lot else that could change.

Many thanks SAIST. That was a very informative post and nicely elucidates the problem. I have learned a great deal.

I have an older gateway solo 9550. I have been using Linux on it since it was new (4 or 5 years ago). Sometimes it just hard freezes up like yours is doing. I ended up trying different distro's until I hit one that doesnt do it. Mepis didnt used to do it, that was wayyyyy back when. I finally settled on Dream Linux for it, and the lock ups have gone away.

[ebbing]

I have just had a quick look on linux laptops and there are two gateways the same as your listed. Don't know if you could gleen some infor from one of those installations that might help.

http://www.linux-on-laptops.com/gateway.html

Also have you checked the Gateway web site for a bios upgrade??

Tim

Thanks for the pointer ebbing.

I checked the link and tried to contact the authors. One of them running SUSE 10.1 64 bit (I had also freezing problems in that distro) and he didn't get back to me. The other runs Ubuntu 6.10 32bit and he informed he doesn't have any freezing problem. Not sure if this could be 32bit vs. 64bit kernel issue, or something is broken in my HW but for reasons unknown does not affect Windows XP.

After making sure I got all the latest updates from Gateway, I then tried for a line the Siast posts had inspired me. In the bios setting, I found an option to disable the power saving C-states, or enable "C2 and C3" (the default) or "C2" only.
I tried all three options and freezing still persisted.
I also noticed that running (using the default BIOS power saving options)

# cat /proc/acpi/processor/CPU0/power
active state:            C2
max_cstate:              C8
bus master activity:     04444221
states:
    C1:                  type[C1] promotion[C2] demotion[--] latency[000] usage[00127250]
   *C2:                  type[C2] promotion[C3] demotion[C1] latency[018] usage[02284410]
    C3:                  type[C3] promotion[--] demotion[C2] latency[999] usage[00000625]

Shows the C3 is rarely used. This is not a healthy sign as the link:
http://acpi.sourceforge.net/wiki/ind...StateIsNotUsed
would suggest.

I noticed a couple of more things:

1. Playing music (using Amarok) reduced the likelihood of hard freeze, but is does not eliminate it completely. It froze when the music was playing and I could hear through my speaker the last few milliseconds played repeating over and over (like a broken record).
2. I never had the laptop freeze when I set the cpu frequency policy to "Performance" (this is the default MEPIS 6.5 settings when the computer is Powered). I have changed that policy to dynamic as it is undesirable to have the laptop humming at all times.

[carlops]

Maybe you ought to check if powersave has the correct speedstep module loaded for your processor....