https://bugzilla.kernel.org/show_bug.cgi?id=63111
--- Comment #11 from Aaron Lu <[email protected]> --- The ASL code initialize initial brightness level to 100, but only for OS that is pre-vista. Don't know why it does this... The _INI method is run during the ACPI device is first discovered. Method (_INI, 0, NotSerialized) // _INI: Initialize { If (LLess (OSYS, 0x07D6)) { Store (0x64, BRTL) } ... ... } The _BQC method is used to tell the current brightness level Method (_BQC, 0, NotSerialized) // _BQC: Brightness Query Current { Return (BRTL) } Since it is not initialized in _INI(as we report to firmware we are Windows 2012), the video module thought the initial brightness level is 0 and then set level 0. The cmdline option use_bios_initial_backlight=0 is used to tell video module that the initial backlight level firmware reported is wrong and do not use it. -- You are receiving this mail because: You are watching the assignee of the bug. ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135991&iu=/4140/ostg.clktrk _______________________________________________ acpi-bugzilla mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
