I tested workaround GRUB_CMDLINE_LINUX="acpi_backlight=vendor acpi_osi='\"!Windows 2009\"'"
with latest 11.04 kernel from kernel-ppa (2.6.39-0-generic #5~20110427-Ubuntu SMP Wed Apr 27 15:27:41 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux). Workaround works e.g. I am able to change display brightness with function keys (Asus UL30A), but dmesg still prints out various error messages like: [ 92.320754] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110316/dsutils-763) [ 92.320767] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node ffff880138e38550), AE_AML_NO_RETURN_VALUE (20110316/psparse-536) [ 92.320788] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node ffff880138e3fcd0), AE_AML_NO_RETURN_VALUE (20110316/psparse-536) [ 92.757691] ACPI Error: Result stack is empty! State=ffff880111500400 (20110316/dswstate-98) [ 92.757710] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110316/dsutils-646) [ 92.757721] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110316/dsutils-763) [ 92.757734] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node ffff880138e38550), AE_AML_NO_RETURN_VALUE (20110316/psparse-536) [ 92.757756] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node ffff880138e3fcd0), AE_AML_NO_RETURN_VALUE (20110316/psparse-536) I suppose now that those lockups are due MTRR error with video memory allocation, situation is indeed better with 2.6.39 but MTRR error still causes minor "stickiness" of graphics performance every now and then. [ 0.000000] MTRR default type: uncachable [ 0.000000] MTRR fixed ranges enabled: [ 0.000000] MTRR variable ranges enabled: [ 15.264935] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining [ 15.264941] [drm] MTRR allocation failed. Graphics performance may suffer. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/566193 Title: luminosity screen on a laptop cannot be set -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
