display black: how to change backlight/pcf50633-bl/actual_brightness ?

[Harald Koenig]

Hi,

sometimes my FR just stays "black" while the Xglamo is still responsive.
"actual_brightness" is zero, but it's not writable, so I can't change it
from the shell:

root at om-gta02:~# head  /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/*brightness
==> /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/actual_brightness <==
0

==> /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/brightness <==
63

==> /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/max_brightness <==
63

root at om-gta02:~# ls -l /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/*brightness
-r--r--r--    1 root     root            0 Sep 19 15:04 /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/actual_brightness
-rw-r--r--    1 root     root            0 Sep 19 15:05 /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/brightness
-r--r--r--    1 root     root         4096 Sep 19 15:04 /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/max_brightness


root at om-gta02:~# echo 63 > /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/actual_brightness
bash: /sys/devices/platform/s3c2440-i2c/i2c-adapter/i2c-0/0-0073/backlight/pcf50633-bl/actual_brightness: Permission denied




what can I do or check to switch on the the display ?

btw:

root at om-gta02:~# apm -s
apm: Device or resource busy



Harald
-- 
"I hope to die                                      ___       _____
before I *have* to use Microsoft Word.",           0--,|    /OOOOOOO\
Donald E. Knuth, 02-Oct-2001 in Tuebingen.        <_/  /  /OOOOOOOOOOO\
                                                    \  \/OOOOOOOOOOOOOOO\
                                                      \ OOOOOOOOOOOOOOOOO|//
                                                       \/\/\/\/\/\/\/\/\/
Harald Koenig                                           //  /     \\  \
koenig at tat.physik.uni-tuebingen.de                     ^^^^^       ^^^^^