# HP Probook no brightness fn keys working.

## Markand

Hi,

I've got a new HP Probook 4510s, I tried ubuntu before installing gentoo on it. With Ubuntu I could use the fn-keys to change the brightness and it worked.

Here on Gentoo it seems to does not work. But I have <*> Video in my kernel power mamagement subsection so I don't know where to search now.

David.

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## WastingBody

I searched around for a little bit, but didn't really find anything. Perhaps you could boot the Ubuntu livecd, and use "lsmod" to see what modules are loaded. Maybe one of them will give you a hint.

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## K T A

I have a Probook 4710s and the keys do not work either - I can change the brightness manualy:

```
echo "n" > /sys/class/backlight/acpi_video0/brightness
```

n being a number from 1-10 - I can assign shortcuts easy enough using fluxbox keys - but if the system is idle for about five minutes and I use the keyboard or mouse after that time the brightness is reset to the highest level...

KTA

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