# The Ubuntu Forum Community > Ubuntu Official Flavours Support > Hardware > [SOLVED] screen Brightness ste to 0% upon log in in HP G62

## czeem86

hello everybody,
i have HP G62 a20SE Notebook with double graphic cards: Intel and ATI
the ATI does not work but this is not a big problem for me now
the main problem is that when the Ubuntu 12.04 starts up and reaches the login screen the brightness goes off and i can feel that everything is just working and i can't see anything anymore!
but when i login to the safe mode settings (recovery mode) it work fine and i notice that the brightness is set to 0% and although i keep changing it it still goes back every time to 0%

could somebody please help me?

thanks in advance

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## czeem86

Solved:


a friend has helped me to solve this

so i want to share the solution with others that might have the same issue:

type in the terminal:

sudo sed "s/\(GRUB_CMDLINE_LINUX=\)\"\"/\1\"acpi_osi=Linux acpi_backlight=vendor\"/" /etc/default/grub -i 
then type:

sudo update-grub

then type:

sudo reboot



hopefully it will work

best wishes

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## cmcanulty

works on HP G72t thank you!!!Can you explain that command I wonder what it does and how

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## anoopp

Thanks a lot. It resolved the same issue with HP 630 and Ubuntu 12.04  :Razz:

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## vinmar

This fixed blank screen at login on my HP G6, thanks for posting back with the solution!

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## Dunpostin

Worked for me also.Had same problem on HP Pavilion G4. I'm also wondering what exactly that command does.

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## Toz

*acpi_osi=Linux* - sometimes a bios will disable functionality if Windows is not detected. This command forces it to use all functionality.

*acpi_backlight=vendor* - tells the kernel to use a vendor specific acpi driver (e.g.. sony_acpi, thinkpad_acpi) instead of the default video module. Helps in fixing backlight issues in some cases.

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## gerrygprs

> Solved:
> 
> 
> a friend has helped me to solve this
> 
> so i want to share the solution with others that might have the same issue:
> 
> type in the terminal:
> 
> ...




Thank you. This worked for HP 630 laptop. Running Ubuntu 12.04

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## kevmehv

> Solved:
> 
> 
> a friend has helped me to solve this
> 
> so i want to share the solution with others that might have the same issue:
> 
> type in the terminal:
> 
> ...



I came across this solution and it worked (kinda).  But I do have a problem...

After applying this solution my laptop now loads at what appears to be 50% screen brightness, which is much better than the default of 0% that I was experiencing before.  BUT now I've lost brightness controls all together!  It loads at about 50% brightness but stays there.  When I go into the brightness settings and try to adjust the brightness I'm able to move the slider but the screen does not change brightness levels, but it used to before I applied the solution.

Any ideas??

Ps.  I've spent the last couple of house digging through the web for a solution but none of them worked for me.  So I'm hoping someone here can help  :Very Happy: 

Acer One 200 series, Ubuntu 12.04

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## AshNova

> Solved:
> 
> 
> a friend has helped me to solve this
> 
> so i want to share the solution with others that might have the same issue:
> 
> type in the terminal:
> 
> ...


This worked for me on HP dv6 3032tx running 12.04.2 64 bit with Kernel Linux 3.5.0-27-generic.

Thank you.

But now the brightness keys don't work.

However that doesn't matter as I always use it at max brightness  :Smile:

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## czeem86

Hallo everyone
I'm trying to install the new version of Ubuntu using a boot CD and upod starting the install the screen goes black  :Sad: (
could somebody please help?

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## ScumCoder

> Hallo everyone
> I'm trying to install the new version of Ubuntu using a boot CD and upod starting the install the screen goes black (
> could somebody please help?


I had the same issue on my Acer P3-171 with every Linux distro, including Ubuntu. In the end I just connected an external display via HDMI.

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## cmcanulty

i had to set nomodeset on the install, need somebody better to explain it though as I forget

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