Screen brightness strange behaviour Dell Inspiron 9400

[bebber]

I have just installed Linux Mint 12 32-bit on my Dell Inspiron 9400 (a.k.a. E1705), and have problems with screen brightness.
Specifically, the screen brightness slider value (from low to high) does not map to the actual screen brightness.
There appear to be 21 levels of brightness available on the slider (accessed through screen settings or using the Fn hotkeys), but these levels do not correspond to the actual brightness of the screen.
The highest value does make the screen brightest, but the next level down makes the screen dim, and the next level after that makes it bright again, and so on (rather hapharzardly).
It must be that whatever is controlling the relationship between the software value and the hardware is not working correctly.
The graphics card is Intel 945GM x86/MMX/SSE2
I have searched and there do seem to be similar threads, but I have no idea whether my problem is related to these others.
I was running Ubuntu 10.04 previously and did not experience this problem.

[Danko8321]

I have just installed Linux Mint 12 32-bit on my Dell Inspiron 9400 (a.k.a. E1705), and have problems with screen brightness.
Specifically, the screen brightness slider value (from low to high) does not map to the actual screen brightness.
There appear to be 21 levels of brightness available on the slider (accessed through screen settings or using the Fn hotkeys), but these levels do not correspond to the actual brightness of the screen.
The highest value does make the screen brightest, but the next level down makes the screen dim, and the next level after that makes it bright again, and so on (rather hapharzardly).
It must be that whatever is controlling the relationship between the software value and the hardware is not working correctly.
The graphics card is Intel 945GM x86/MMX/SSE2
I have searched and there do seem to be similar threads, but I have no idea whether my problem is related to these others.
I was running Ubuntu 10.04 previously and did not experience this problem.

Yes, there are some incompatibility issues with Dells and the Brightness keys. I own a Lenovo, but that happens to me as well. Pitifully, the only thing you can do right now is to adjust the screen brightness directly from gnome-control-center ("Screen") and see if that helps.

[bebber]

It seems strange that Ubuntu 10.04 worked fine, but Mint 12 doesn't.
Are there no configuration files that can be altered?
I don't know how the system works, but I imagine there is some kind of conversion of the screen brightness value into the voltage supplied to the backlight, and it is the converter that needs adjusting.

[Danko8321]

It seems strange that Ubuntu 10.04 worked fine, but Mint 12 doesn't.
Are there no configuration files that can be altered?
I don't know how the system works, but I imagine there is some kind of conversion of the screen brightness value into the voltage supplied to the backlight, and it is the converter that needs adjusting.

Yeah... Don't do that manually.

It could be dangerous if you don't know what you're doing.

However, I have a couple of doubts regarding your system and hardware configuration; would you mind posting the results of the following commands here?

Code: Select all

inxi -F

and

Code: Select all

lspci

That should give me some info about your system and, hopefully, what is causing the strange behaviour of the keys. You probably need an XOrg or Kernel update, but I suggest you not to do any of those until you are sure that will fix it. For the moment at least, post back the output of those two commands.

Cheers. Danko.

[bebber]

Hi Danko, thanks for taking a look.

Here is the result from inxi -F:
System: Host bebber Kernel 3.0.0-12-generic i686 (32 bit) Desktop Gnome Distro Linux Mint 12 Lisa
Machine: System Dell (portable) product MP061
Mobo Dell model 0FF049 Bios Dell version A03 date 07/29/2006
CPU: Dual core Intel CPU T2050 (-MCP-) cache 2048 KB flags (nx sse sse2 sse3)
Clock Speeds: (1) 800.00 MHz (2) 800.00 MHz
Graphics: Card: Intel Mobile 945GM/GMS 943/940GML Express Integrated Graphics Controller
X.Org 1.10.4 drivers intel unloaded: fbdev,vesa Resolution 1440x900@59.9hz
GLX Renderer Mesa DRI Intel 945GM x86/MMX/SSE2 GLX Version 1.4 Mesa 7.11
Audio: Card Intel N10/ICH 7 Family High Definition Audio Controller driver HDA Intel Sound: ALSA v: 1.0.24
Network: Card-1 Broadcom BCM4401-B0 100Base-TX driver b44
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Card-2 Intel PRO/Wireless 3945ABG [Golan] Network Connection driver iwl3945
IF: wlan0 state: up mac: 00:13:02:dc:4c:a6
Drives: HDD Total Size: 320.1GB (54.3% used) 1: /dev/sda ST9320423AS 320.1GB
Partition: ID:/ size: 293G used: 162G (59%) fs: ext4 ID:swap-1 size: 1.06GB used: 0.06GB (6%) fs: swap
Sensors: Error: You do not have the sensors app installed.
Info: Processes 131 Uptime 1 day Memory 371.5/992.9MB Client Shell inxi 1.7.7

Here is result from lspci:
00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 01)
00:1c.1 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 2 (rev 01)
00:1c.3 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 4 (rev 01)
00:1d.0 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation N10/ICH 7 Family SMBus Controller (rev 01)
03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller
03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19)
03:01.2 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 0a)
03:01.3 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05)
0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02)