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Old 01-07-11, 07:11 AM   #101
guillaumezin
Registered User
 
Join Date: Dec 2009
Posts: 26
Default Re: Linux backlight driver

Quote:
Originally Posted by Zem View Post
Here it is:
Code:
/sys/module/nvidiabl/parameters$ cat *
128000
7000
0
2603
Ok, I have no clue with this, the wole register is screwed up. We will try to log writes and reads of the register. This is a bit dangerous, so do it only if you're a bit familiar with Linux command line.

Code:
sudo nano /etc/rc2.d/S00mmiotrace
containing:
Code:
#!/bin/bash

echo mmiotrace > /sys/kernel/debug/tracing/current_tracer
echo Starting > /sys/kernel/debug/tracing/trace_marker

modprobe -r nvidia
modprobe -r nvidiabl

echo Inserting nvidia > /sys/kernel/debug/tracing/trace_marker

modprobe nvidia

echo Inserting nvidiabl > /sys/kernel/debug/tracing/trace_marker

modprobe nvidiabl
then:
Code:
sudo chmod +x /etc/rc2.d/S00mmiotrace
Reboot.

After reboot, Ubuntu may complain that the graphic driver didn't initialize properly. Ask to try again. If you're stuck, do CTRL+ALT+F2, login, type "sudo rm /etc/rc2.d/S00mmiotrace" then "sudo reboot". If your desktop environment boots up fine:

Code:
cat /sys/kernel/debug/tracing/trace_pipe > ~/mydump.txt &
sudo su -c "echo playing with the backlight > /sys/kernel/debug/tracing/trace_marker"
Keep the terminal window open and change you backlight brightness up and down a bit. After that:

Code:
sudo su -c "echo break backlight register > /sys/kernel/debug/tracing/trace_marker"
And play a movie fullscreen until you reproduce your problem. Then:

Code:
sudo su -c "echo nop > /sys/kernel/debug/tracing/current_tracer"
sudo rm /etc/rc2.d/S00mmiotrace
Reboot and publish here the content of the file mydump.txt from your home directory. If the file is big, keep only the end starting with the text string "playing with the backlight".

Thank you.

Guillaume

Last edited by guillaumezin; 01-08-11 at 07:58 AM.
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