Author Topic: Screen brightness  (Read 5033 times)

Scripter

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Screen brightness
« on: September 13, 2009, 07:24:10 PM »
Hi,

I love the bright screen, but sometimes in a darker room it can be too bright.

Has any one found a way of 'turning down' the brightness like on a normal laptop?

It would also help to increase the battery life!

Sensible answers only please ..... ;D

Scripter.
CnMBook, original OS, Backlight Control Kernel.

Mijzelf

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Re: Screen brightness
« Reply #1 on: September 14, 2009, 07:55:36 AM »
Ard van Breemen has compiled a kernel with backlight control. You can control the backlight with Fn+F4 and Fn+F5.

Another way is typing 'echo NR > /proc/jz/lcd' on a command prompt, where NR is a number between 0 and (I thought) 300. 0 is minimum, and 300 max. And of course you can write scripts and menu functions to do so. You can read the current bightness with 'cat /proc/jz/pwm0/duty'

Scripter

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Re: Screen brightness
« Reply #2 on: September 14, 2009, 08:15:59 PM »
Thanks for the info Mijzelf.

I'm not comfortable going for the alternative kernel.

But I like the idea of using /proc/jz

'cat /proc/jz/pwm0/duty' displays 0x012c which is 300.

I haven't had any luck with 'echo NR > /proc/jz/lcd'
using a decimal number does nothing, using a hex number flashes the screen.

But it looks promising

Scripter
CnMBook, original OS, Backlight Control Kernel.

Leven2e

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MBR
« Reply #3 on: September 14, 2009, 08:21:49 PM »
changing the MBR is really not a big deal,also you will have better sound volume ;much louder,good if you use your minilaptop as an internet radio (as myself)!!
The Hun.

Mijzelf

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Re: Screen brightness
« Reply #4 on: September 15, 2009, 08:43:39 AM »
As I remember well it should be a decimal value. Which values did you test? 300 steps seems to give a high granularity, but on my laptop all values above 100 are 'very bright'. Try 50 or something like that.

Scripter

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Re: Screen brightness
« Reply #5 on: September 15, 2009, 07:50:18 PM »
I've tried several numbers between 6 and 300, with no success.
CnMBook, original OS, Backlight Control Kernel.

jwhd

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Re: Screen brightness
« Reply #6 on: October 17, 2009, 11:59:47 AM »
 :)Thanks for the post about the alternative kernel, which enables you to alter the screen brightness easily. I like it very much. However, my Huawei E220 3G dongle doesn't work after installing the kernel. Any ideas on how to make the dongle work without having to revert to my previous kernel? Many thanks

Unhban

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Re: Screen brightness
« Reply #7 on: October 17, 2009, 12:28:11 PM »
Hi jwhd. Have a look at post 52 here, it may help:

http://linuxlaptopforum.ark2webdesign.co.uk/index.php/topic,643.msg4938.html#msg4938

Also, there is a posting, somewhere.... where one of the files should have 188,0 in instead of 180,0... or vice versa!, but this was to do with one of the OSs released and not the kernel.

BTW, my E220 works fine with the original OS and latest kernel, but of course you lose the screen brightness change. C'est la vie!

Unh.

Mijzelf

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Re: Screen brightness
« Reply #8 on: October 19, 2009, 01:23:07 PM »
Which lines are added to dmesg, when plugging in the dongle?

jwhd

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Re: Screen brightness
« Reply #9 on: October 24, 2009, 07:58:43 PM »
Thanks Unhban, I have successfully   restored my 3G dongle to working order by reverting to the V70 kernel. I will keep trying with the other kernel (which gives screen brightness control).  I suppose you can't have it all

Scripter

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Re: Screen brightness
« Reply #10 on: November 05, 2009, 08:30:35 PM »
Well, I finally bit the bullet and changed the kernel.

The good news: Hurray
Now I can change the brightness to suit the ambient light level. 
More good news: Hurray
And as I thought, the battery does last longer with lower brightness.

And now for the bad news: Boo
And yes my E220 stopped working.

Is this beginning to sound like a pantomime?

Anyway, I reinstalled driver-modem-v70, it said it was already installed but I carried on anyway, it finished with an error saying it was for v70.
I also reinstalled ap-MobileConnection.

The modem was not detected when plugged in, so I ran huawei_e220_active and ppp-wireless from xterm, and hey presto everything worked.

Who says you cant have it all ;D
CnMBook, original OS, Backlight Control Kernel.