* Joey Lee -- Monday 09 May 2011:
The following is debug patch, and please add kernel parameter drm.debug=0x02 :
The result is with acpi_osi=Linux:
boot phase: [ 3.310274] [drm:intel_panel_get_backlight], get backlight val = 2890 [ 3.310280] [drm:intel_panel_get_backlight], get backlight PWM = 2890 [ 3.310615] [drm:intel_panel_get_backlight], get backlight val = 2890 [ 3.310617] [drm:intel_panel_get_backlight], get backlight PWM = 2890 [ 3.310619] [drm:intel_panel_set_backlight], set backlight PWM = 0 [ 3.310622] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401930 [ 3.310624] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 3.310626] [drm:intel_panel_set_backlight], set backlight level = 0
[ 3.641522] [drm:intel_panel_set_backlight], set backlight PWM = 2890 [ 3.641525] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399040 [ 3.641527] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 3.641529] [drm:intel_panel_set_backlight], set backlight level = 2890
[ 11.410563] video LNXVIDEO:01: Restoring backlight state
brightness up: [no output]
brightness down: [ 152.697127] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 152.697136] [drm:intel_panel_set_backlight], set backlight PWM = 283 [ 152.697141] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401930 [ 152.697146] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 152.697150] [drm:intel_panel_set_backlight], set backlight level = 283
[ 166.720631] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 166.720640] [drm:intel_panel_set_backlight], set backlight PWM = 578 [ 166.720645] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399323 [ 166.720649] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 166.720654] [drm:intel_panel_set_backlight], set backlight level = 578
[ 178.091776] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 178.091784] [drm:intel_panel_set_backlight], set backlight PWM = 861 [ 178.091789] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399618 [ 178.091793] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 178.091797] [drm:intel_panel_set_backlight], set backlight level = 861
[ 188.888370] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 188.888379] [drm:intel_panel_set_backlight], set backlight PWM = 1156 [ 188.888383] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399901 [ 188.888388] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 188.888392] [drm:intel_panel_set_backlight], set backlight level = 1156
[ 196.411657] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 196.411665] [drm:intel_panel_set_backlight], set backlight PWM = 1439 [ 196.411670] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400196 [ 196.411674] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 196.411678] [drm:intel_panel_set_backlight], set backlight level = 1439
[ 201.256229] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 201.256238] [drm:intel_panel_set_backlight], set backlight PWM = 1734 [ 201.256243] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400479 [ 201.256247] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 201.256252] [drm:intel_panel_set_backlight], set backlight level = 1734
[ 206.939838] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 206.939846] [drm:intel_panel_set_backlight], set backlight PWM = 2017 [ 206.939851] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400774 [ 206.939856] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 206.939860] [drm:intel_panel_set_backlight], set backlight level = 2017
[ 213.779732] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 213.779740] [drm:intel_panel_set_backlight], set backlight PWM = 2312 [ 213.779744] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401057 [ 213.779749] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 213.779753] [drm:intel_panel_set_backlight], set backlight level = 2312
[ 222.583806] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 222.583814] [drm:intel_panel_set_backlight], set backlight PWM = 2595 [ 222.583819] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401352 [ 222.583824] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 222.583828] [drm:intel_panel_set_backlight], set backlight level = 2595
[ 229.345860] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 229.345870] [drm:intel_panel_set_backlight], set backlight PWM = 2595 [ 229.345874] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401635 [ 229.345879] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 229.345883] [drm:intel_panel_set_backlight], set backlight level = 2595
brightness up: [ 240.594464] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 240.594474] [drm:intel_panel_set_backlight], set backlight PWM = 2312 [ 240.594479] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401635 [ 240.594483] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 240.594487] [drm:intel_panel_set_backlight], set backlight level = 2312
[ 240.816722] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 240.816730] [drm:intel_panel_set_backlight], set backlight PWM = 2017 [ 240.816734] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401352 [ 240.816739] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 240.816743] [drm:intel_panel_set_backlight], set backlight level = 2017
[ 240.999973] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 240.999981] [drm:intel_panel_set_backlight], set backlight PWM = 1734 [ 240.999985] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189401057 [ 240.999990] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 240.999994] [drm:intel_panel_set_backlight], set backlight level = 1734
[ 241.212456] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 241.212464] [drm:intel_panel_set_backlight], set backlight PWM = 1439 [ 241.212469] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400774 [ 241.212473] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 241.212478] [drm:intel_panel_set_backlight], set backlight level = 1439
[ 241.395611] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 241.395619] [drm:intel_panel_set_backlight], set backlight PWM = 1156 [ 241.395624] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400479 [ 241.395628] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 241.395633] [drm:intel_panel_set_backlight], set backlight level = 1156
[ 242.039460] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 242.039470] [drm:intel_panel_set_backlight], set backlight PWM = 283 [ 242.039475] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189400196 [ 242.039479] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 242.039484] [drm:intel_panel_set_backlight], set backlight level = 283
[ 242.044495] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 242.044502] [drm:intel_panel_set_backlight], set backlight PWM = 283 [ 242.044507] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399323 [ 242.044511] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 242.044515] [drm:intel_panel_set_backlight], set backlight level = 283
[ 242.077032] [drm:intel_panel_get_max_backlight], max backlight PWM = 2890 [ 242.077038] [drm:intel_panel_set_backlight], set backlight PWM = 0 [ 242.077043] [drm:intel_panel_set_backlight], set backlight tmp(1) = 189399323 [ 242.077047] [drm:intel_panel_set_backlight], set backlight tmp(2) = 189399040 [ 242.077052] [drm:intel_panel_set_backlight], set backlight level = 0
m.