You have been subscribed to a public bug: I have NX7400 laptop. Afer power up display backlight is always set to 100% light, independent of brightness settings in previous session. I detected that problem is in acpi kernel driver video.ko and gnome-power- manager. I use ubuntu 8.10 with kernel 2.6.27-7-generic on 64-bit platform. This is a regression bug, because in previous version ubuntu 8.04LTS display backlight works ok.
Aditional comments: I detected that acpi/video.ko kernel 2.6.24 driver in ubuntu 8.04 didn't work and backlight was controlled only by ACPI bios, because /proc/bus/acpi/video/*/backlights always return that backlight is not supported. In kernel 2.6.27 driver return correct backlight values: cat /proc/acpi/video/C085/C144/brightness levels: 100 51 30 37 44 51 58 65 72 79 86 93 100 current: 65 New video driver trying to get current backlight level from ACPI BQI object but it is optional ACPI function. When ACPI does not support BQI object driver will set back-light to maximum value. Pls. see code video.c bellow: if (device->cap._BQC) device->backlight->props.brightness = acpi_video_get_brightness(device->backlight); else device->backlight->props.brightness = device->backlight->props.max_brightness; backlight_update_status(device->backlight); When ACPI BQI is not supported video.ko or gnome-power-manager should save and restore current backlight value from config file. Workaround: Currently I workaround this problem by change kernel driver video.ko to set 50% backlight when BQI object is not found (Pls see patch bellow). I alse changed gnome-power-manager settings by run gconf-editor and set following configuration values in /apps/gnome-power/manager/backlight by changing keys values to: brightness_ac = 50 brightness_battery = 30 brightness_dim_battery = 30 but it is obvious workaround. ** Affects: gnome-power-manager (Ubuntu) Importance: Undecided Status: New -- display brightness is setup to 100% after power up https://bugs.launchpad.net/bugs/291742 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in ubuntu. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs