# ondemand governor failed, too long transition latency of HW

## Robelix

```
ondemand governor failed, too long transition latency of HW, fallback to performance governor
```

Any Ideas what can be causing this?

ThinkPad T23 with Pentium 3 Mobile 1133MHz

kernel: 2.6.28-gentoo-r5

```
dings ~ # cpufreq-info

cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006

Report errors and bugs to linux@brodo.de, please.

analyzing CPU 0:

  driver: speedstep-smi

  CPUs which need to switch frequency at the same time: 0

  hardware limits: 733 MHz - 1.13 GHz

  available frequency steps: 1.13 GHz, 733 MHz

  available cpufreq governors: powersave, ondemand, performance

  current policy: frequency should be within 733 MHz and 1.13 GHz.

                  The governor "performance" may decide which speed to use

                  within this range.

  current CPU frequency is 1.13 GHz (asserted by call to hardware).
```

I use cpufreqd-2.1.1 to switch between powersave for Battery and ondemand for AC

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## Hu

 *Robelix wrote:*   

> 
> 
> ```
> ondemand governor failed, too long transition latency of HW, fallback to performance governor
> ```
> ...

 

Based on the notes in the Kconfig help and in Documentation/cpu-freq/governors.txt, your choice of CPU is causing this.  Not all CPUs can switch frequencies quickly enough to satisfy the ondemand governor.

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## lt.cyx

I have the same with a Celeron-M. And how come it was fast enough up until 2.6.29 and now in 2.6.30 it is not? What changed?

```

processor   : 0

vendor_id   : GenuineIntel

cpu family   : 6

model      : 15

model name   : Intel(R) Celeron(R) M CPU        530  @ 1.73GHz

stepping   : 10

cpu MHz      : 1733.329

cache size   : 1024 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 pse36 clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx lm constant_tsc up arch_perfmon pebs bts pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm lahf_lm

bogomips   : 3458.31

clflush size   : 64

power management:

```

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