On an IBM Thinkpad, I'm experiencing this same problem. It might be a kernel issue, because I did not experience this with the linux kernel 2.6.27-9, as far as I remember. There is a graphical display of the brightness being lowered, but the brightness does not actually lower--it doesn't make a difference if I try via the screen brightness applet or the hardware keys, the effect is the same, brightness is on the highest level. This is a serious issue as I rely on my laptop's battery life. Lenovo Thinkpad X61 Tablet, running Ubuntu Intrepid, all forms of updates (backports, proposed, etc) enabled.
On an IBM Thinkpad, I'm experiencing this same problem. It might be a kernel issue, because I did not experience this with the linux kernel 2.6.27-9, as far as I remember. There is a graphical display of the brightness being lowered, but the brightness does not actually lower--it doesn't make a difference if I try via the screen brightness applet or the hardware keys, the effect is the same, brightness is on the highest level. This is a serious issue as I rely on my laptop's battery life. Lenovo Thinkpad X61 Tablet, running Ubuntu Intrepid, all forms of updates (backports, proposed, etc) enabled.
lspci MMC/MS/ MSPro Host Adapter (rev 21)
00:00.0 Host bridge: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub (rev 0c)
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 0c)
00:02.1 Display controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 0c)
00:19.0 Ethernet controller: Intel Corporation 82566MM Gigabit Network Connection (rev 03)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev f3)
00:1f.0 ISA bridge: Intel Corporation 82801HBM (ICH8M-E) LPC Interface Controller (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) IDE Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) SATA AHCI Controller (rev 03)
00:1f.3 SMBus: Intel Corporation 82801H (ICH8 Family) SMBus Controller (rev 03)
03:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61)
05:00.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ba)
05:00.1 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 04)
05:00.2 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/