dell lcd brightness strange behaviour

[Nicolò Chieffo]

Latitude E6400
the command
sudo dellLcdBrightness -v [0-f]
does not modify the real LCD brightness, but only the value stored in the BIOS, as after executing
sudo dellLcdBrightness
I can see that the value is changed accordingly to the one I selected in the previous command.

ProblemType: Bug
Architecture: i386
Dependencies:
 libgcc1 1:4.3.3-3ubuntu5
 gcc-4.3-base 4.3.3-3ubuntu5
 libstdc++6 4.3.3-3ubuntu5
 findutils 4.4.0-2ubuntu3
 libc6 2.9-0ubuntu10
DistroRelease: Ubuntu 9.04
Package: libsmbios2 2.2.13-0ubuntu1
ProcEnviron:
 PATH=(custom, user)
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: libsmbios
Uname: Linux 2.6.28-8-generic i686

[Nicolò Chieffo (yelo3)]

Oh I found the trick! It does not work until I disable the ambient light sensor. Anyway there's no way to control it in libsmbios

[Jon Armond (jon2000-uk)]

I have the same issue with a Dell Studio 1555. I don't think it has an ambient light sensor. Attached a trace.
Uname: 2.6.30-9-generic amd64
Libsmbios2: 2.2.13-0ubuntu2

[Ivan Zakharyaschev (imz)]

I have a similar problem on linux 4.4.119, but not on linux 3.10.32:

smbios-lcd-brightness --value=1

has a visible effect on linux 3.10.32, but not on linux 4.4.119, though the saved value is modified indeed.

Do you have some ideas?

python-module-smbios-2.3.3-alt1.0.g4fec2ad.noarch
libsmbios-2.3.3-alt1.0.g4fec2ad.x86_64
smbios-utils-2.3.3-alt1.0.g4fec2ad.x86_64

[Ivan Zakharyaschev (imz)]

https://github.com/dell/libsmbios/issues/42