Eee Top, intel driver: backlight off

Uplink advantis at
Thu Nov 27 14:01:20 PST 2008

Hello everyone,

I recently received two shiny Asus Eee Top ET1602 units to play with. I
am to run Linux on them, and pretend that the Windows XP Home that came
with them is not there. But I have a problem... the LCD backlight is
turned off when X starts with the intel driver.

I use Ubuntu 8.10 (intel driver 2.4.1, libdrm 2.3.1, kernel 2.6.27). As
soon as X starts, the backlight turns off and there's no way to turn it
back on while X is on display. Switching to a console turns the
backlight on, switching back to X turns it off again.

The display is connected on the LVDS connector (according to the Windows
video driver), but when I run "xrandr --properties" there's something
wrong there: the range for the BACKLIGHT priperty is (0,0). I tried
switching the BACKLIGHT_CONTROL property to different values (starts
with 'native'), but to no avail. I hacked the drivers so the range
matches that of my laptop, which is (0,10781) in "combination" mode, but
still no effect on the backlight.

The "vesa" driver works fine. Even more, the touch screen works with the
evtouch driver without much hassle: . All that's missing is
the actual picture.

I tried the 2.5.1 driver from Debian experimental (without upgrading any
drm kernel modules though) and I got the same result.

At this point, I gave up on researching it on my own. Can someone help
me fix the backlight controls for this machine?

    Radu C

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