[SOLVED] Backlight control on hp pavillion dv6 (sandy+ati)

[Fran]

Has anyone managed to control the backlight on a recent hp pavillion dv6?

If I boot normally, I have two directories in /sys/class/backlight, called acpi_video0 and acpi_video1 (I assume one for the intel, one for the amd 6770m). However, echoing any value to acpi_videoX/backlight does nothing. The value is set, but the backlight doesn't change.

If I boot using "acpi_osi=Linux acpi_backlight=vendor", as suggested on the interwebz, I get an empty /sys/class/backlight. Some people talk about an "intel_backlight" directory appearing there (Ubuntu users mainly), but I haven't managed to get it. I don't see anything that suggests "intel backlight" in the kernel, so maybe it's an ubuntu patch.

Any clue?

Thanks

(edit) Solved. I had to compile "Lowlevel Backlight controls" built-in, not as a module. That, together with "acpi_backlight=vendor" gives me the intel_backlight sys directory, from where I can change the backlight.
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~amd64 13.0 // linux-3.9 // gcc-4.8 // glibc-2.17 // xorg-server-1.14 // dwm-6.0