Uncontrollable brightness with Ubuntu 12.10 on HP Pavilion g7-2220 Notebook

[josvanr]

I just did an update, kernel is now 3.2.0-35-generic, and the problem has gone for hp envy 17 2100ed.

One down, x to go ......

[Toz]

Retrying the above for-loop with the backlight parameter yields:

/sys/class/backlight/*
cat: /sys/class/backlight/*/brightness: No such file or directory
cat: /sys/class/backlight/*/max_brightness: No such file or directory

It's just an empty directory now that the parameter is set.

The result of lspci | grep VGA is:

00:01.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Trinity [Radeon HD 7520G]

Try these commands:

sudo setpci -s 00:01.0 F4.B=FF
sudo setpci -s 00:01.0 F4.B=0
sudo setpci -s 00:01.0 F4.B=80

If no luck, try removing the acpi_backlight=vendor parameter and trying those commands again.

[Uncuddly]

The above commands produce no discernible difference with or without the backlight parameter. It's good to hear that josvanr has resolved the issue with the HP Envy, however!

[Toz]

I can't seem to manipulate your backlight interface. I think you're next best bet would be to try to get the proprietary drivers to work on your laptop.

According to this bug report (https://bugs.launchpad.net/ubuntu/+s...y/+bug/1068488), there is a problem with installing proprietary drivers because of a missing package. You might be suffering from this problem when you try to enable to proprietary drivers and end up with a blank screen on reboot.

If you want to try getting the proprietary drivers installed again, try installing linux-headers-generic before enabling the proprietary drivers.

If on restart you still get a blank screen, you should be able to regain access to the system by passing the nomodeset kernel parameter on startup. See "How to temporarily set kernel boot options on an installed OS (not wubi)" here for info on how to set it on startup.

[Uncuddly]

The system states that linux-headers-generic is already installed. It dates to October so it must be from the DVD and therefore available during the previous attempts to use the proprietary drivers.

Thanks for the nomodeset suggestion, though. I will definitely try that next time things go belly-up.

[ShubhN]

Can you open a terminal window, run the following command and post back the results (it will identify your backlight interfaces):

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

Maybe we can manually manipulate the brightness.

Thanks for that. It was really req, bacause i started planning to go back to win7 since my eyes started responding to that much brightness. THANKS AGAIN IN BOLD

[chris.rapson]

just like josvanr I'm following this thread to see if a solution turns up for older Envy hardware. As I understand it, the OP still has maxed out brightness? I've also had no success with grub settings and proprietary drivers only created more problems.

I'm running kernel 3.11.0-12-generic with Kubuntu 13.10

[Toz]

just like josvanr I'm following this thread to see if a solution turns up for older Envy hardware. As I understand it, the OP still has maxed out brightness? I've also had no success with grub settings and proprietary drivers only created more problems.

I'm running kernel 3.11.0-12-generic with Kubuntu 13.10

Hello @chris.rapson and welcome to the forums.
Do you have the same system with an ATI card? What does the following command return:

lspci -k | grep -iA2 VGA

Can you also run the following command so we can see your current backlight interfaces:

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done