Page 1 of 5

ACPI Kernel issue

Posted: Sun Jun 07, 2009 9:31 pm
by ekips
Does the build of Ubuntu in the recovery image contain any special patches in the kernel?

I have put on the latest kernel 2.6.29 first just the default settings.
I found that when downloading data (scp or wget) the whole system would just stop, at first i thought it was just the network interface as it would not respond to a ping when this happened. But i found this would even cause the blinking cursor on the login prompt to stop flashing. Anything running would basically just stop. This condition was recoverable by pressing any key on the keyboard or plugging/unplugging a device. When it resumed it continued as if nothing happened (unless remote end had timed out waiting)

After some other troubleshooting i recompiled the kernel without APM or ACPI with this new kernel the issue did not happen.
I then recompiled with just ACPI and the issue was back.

So was the recovery image kernel patched or is this an issue with the newer kernels?

Re: ACPI Kernel issue

Posted: Tue Jun 09, 2009 11:09 am
by Denis
Recovery image kernel includes some patches, but they are not related to ACPI, APM or networking. We will put kernel sources in dedicated ppa soon

Re: ACPI Kernel issue

Posted: Sun Jun 14, 2009 10:56 pm
by prj
Hi ekips, I had similar problems with 2.6.28. The system seems to hang when changing C-States, but by disabling C-states in the BIOS and using GV3 instead the problem went away. Hope it helps.

Re: ACPI Kernel issue

Posted: Mon Jun 15, 2009 9:08 pm
by ekips
Thanks! that worked great :D

Will there be any disadvantage to having C-States disabled?
From what ive read power consumption seems to be the main reason for C-States but with the fitpc2 its not really something that needs lowered much more.

Re: ACPI Kernel issue

Posted: Tue Jun 16, 2009 1:37 pm
by prj
As long as you have GV3 selected in the BIOS you get CPU frequency scaling. It seems to work just as you'd expect it to work. But if you disable both C-States and GV3 you won't get any scaling at all.

Re: ACPI Kernel issue / X freeze

Posted: Mon Jun 29, 2009 9:17 pm
by Mylife
Kernel 2.6.28-13-generic (Ubuntu 9.04).

I had exactly the same problem as ekips (Spike?) but with an X11 session.
I mean that it happened when logging to my couple of fit-PCs through XDMCP with another computer.

Pressing a key on the keyboard didn't help, but slightly pressing the power button solved the problem for a minute or two. That was sure not a fix (especially if I had to connect with another computer far from my fit-PCs).

Following prj's tip, I disabled C-states in the BIOS and used GV3 instead.
Now, everything works like a charm.
Thank you prj. Thanks a lot ! :D

Re: ACPI Kernel issue

Posted: Fri Jul 10, 2009 10:27 am
by prj
My theory about this issues is that Hyperthreading is not enabled/supported at all in 8.04, could someone verify this? The thing with newer kernels is that they do support HT and therefore the bug appears.

Can someone enlighten me? Posting the /proc/cpuinfo from 8.04 should be enough

Thanks

Re: ACPI Kernel issue

Posted: Fri Jul 10, 2009 5:26 pm
by Mylife
Maybe we could create a new topic (if the forum rules allow it) so that people with the 8.04 could help us with posts like "cat /proc/cpuinfo" ?

I'm not ready to make another partition for a 8.04 beside my 9.04 before leaving on vacations ... :?

Re: ACPI Kernel issue

Posted: Sun Jul 12, 2009 4:52 am
by rbordel
Here's your enlightenment:

fitpc2:~$ uname -a
Linux fitpc2_001 2.6.24.7-v1-fitpc2 #49 PREEMPT RT Mon Apr 20 10:37:43 EDT 2009 i686 GNU/Linux

fitpc2:~$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU Z530 @ 1.60GHz
stepping : 2
cpu MHz : 1600.000
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 xtpr lahf_lm
bogomips : 3194.09
clflush size : 64

Re: ACPI Kernel issue

Posted: Sun Jul 12, 2009 8:33 pm
by prj
Thanks!

HT is visible in the flags but I think it's missleading. I suspect the kernel is compiled without support for SMP. Could you do :
uname -a

It should be reported there.