Here's how I experience this bug on an Asus UL30A. The bug is in... * 2.6.34 (vanilla) * 2.6.35.4 (vanilla) * 2.6.35-21-generic (after upgrading to ubuntu 10.10beta) * 2.6.35-22-generic
It occurs with... * default kernel parameters * acpi_backlight=video * acpi_osi=Linux == bug experience #1 == And in all these cases I see the following output: $ cat /proc/acpi/video/VGA/LCDD/brightness levels: 5 11 17 23 29 35 41 47 53 59 65 72 79 86 93 100 current: 59 The value seems to be chosen randomly from this list after booting. I can set it manually only from 5 to 47. If I want to set a higher value, I get a "invalid value" error. And best of all: the values are not linear! Screen brightness is higher at 5 than at 11, but goes higher at 17 than at 11, and so on. When trying to change the brightness with the Fn keys of my laptop, there's a KDE app showing brightness. But it doesn't change... it somehow seems to interrupt the system, because everything's a bit slower for a second and the brightness app doesn't disappear as soon as it normally does. But after a few seconds, everything's fine - except that the brightness has a new random value. It might be brighter or darker, no matter which key I pressed. == bug experience #2 == And then there's a slightly different experience of this bug, when I use * acpi_backlight=vendor Here I can't use the /proc file, because: $ cat /proc/acpi/video/VGA/LCDD/brightness <not supported> But the KDE brightness app works (or does not) the same way as before. == bug experience #3 == And finally another slightly different experience of this bug. When I use the following kernel parameter... * acpi_osi= ...I can change the brightness successfully and in a linear way when using the Fn keys. They work fine. Unfortunately the KDE brightness app seems to be gone and I also can't use /proc, because: $ cat /proc/acpi/video/VGA/LCDD/brightness <not supported> == laptop details == Asus UL30a 00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) dmesg doesn't show any useful information related to this stuff. -- Screen brightness can not be adjusted in Lucid with Intel Arrandale graphics https://bugs.launchpad.net/bugs/573984 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
