Kernel 2.6.28-4.10 fixes this problem for me in Jaunty.
For the first time the brightness keys work correctly on my Asus B50A laptop.
However in /var/log/messages these messages appear when pressing brightness up/down keys:
Jan 13 22:13:54 asus kernel: [ 181.876404] ACPI Error (dswstate-0097): Result stack is empty! State=ffff880128a22000 [20080926] Jan 13 22:13:54 asus kernel: [ 181.876417] ACPI Exception (dsutils-0645): AE_AML_NO_RETURN_VALUE, Missing or null operand [20080926] Jan 13 22:13:54 asus kernel: [ 181.876426] ACPI Exception (dsutils-0762): AE_AML_NO_RETURN_VALUE, While creating Arg 1 [20080926] Jan 13 22:13:54 asus kernel: [ 181.876437] ACPI Error (psparse-0524): Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node ffff88013f81de60), AE_AML_NO_RETURN_VALUE Jan 13 22:13:54 asus kernel: [ 181.876588] ACPI Error (psparse-0524): Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node ffff88013f842440), AE_AML_NO_RETURN_VALUE
Kernel 2.6.28-4.10 fixes this problem for me in Jaunty.
For the first time the brightness keys work correctly on my Asus B50A laptop.
However in /var/log/messages these messages appear when pressing brightness up/down keys:
Jan 13 22:13:54 asus kernel: [ 181.876404] ACPI Error (dswstate-0097): Result stack is empty! State=ffff88012 8a22000 [20080926] NO_RETURN_ VALUE, Missing or null operand [20080926] NO_RETURN_ VALUE, While creating Arg 1 [20080926] PCI0.VGA_ .UPBL] (Node ffff88013f81de60), AE_AML_ NO_RETURN_ VALUE PCI0.SBRG. EC0_._Q0F] (Node ffff88013f842440), AE_AML_ NO_RETURN_ VALUE
Jan 13 22:13:54 asus kernel: [ 181.876417] ACPI Exception (dsutils-0645): AE_AML_
Jan 13 22:13:54 asus kernel: [ 181.876426] ACPI Exception (dsutils-0762): AE_AML_
Jan 13 22:13:54 asus kernel: [ 181.876437] ACPI Error (psparse-0524): Method parse/execution failed [\_SB_.
Jan 13 22:13:54 asus kernel: [ 181.876588] ACPI Error (psparse-0524): Method parse/execution failed [\_SB_.