Comment 20 for bug 568611

Testers -- thanks very much for your valuable feedback. Note that this "i915 brightness" fix has NOT yet been applied to the Ubuntu development kernel, but it has now been submitted for comments to the relevant upstream development teams. For the time being, the fix is only available in the test kernels that I post to this bug, which I'll need to update after each intervening kernel release.

The latest build for Lucid is available here: http://kernel.ubuntu.com/~kamal/i915bri~3e/latest-lucid/ (source patch in the parent directory). To install this kernel, download the two .deb files and install them using:
    sudo dpkg -i linux*kamal*.deb

Note that the test kernel also includes the fixes for LP: #553498 and LP: #573120 (even though the acpi_backlight= boot option is not required for the Dell Studio 155x with this kernel).

After rebooting, verify that "dmesg | grep backlight" yields the following line, signifying that the backlight will be controlled by the i915 driver:
    acpi device:04: registered as backlight/i915

Feedback to this bug report will be much appreciated, from Intel GPU-based (i915 driver) systems.