help with backlight control and memory

[Wojciech Puchar]

>       bought new laptop. it's lenovo B590
>
>       most things works fine. but brightness control keys doesn't work after FreeBSD is loaded. they work before it.
>
>       i don't ask for a solution but any point to start. What should i check?
> 
> 
> Have you loaded the acpi_video module? What does `sysctl hw.acpi.video` say?

no i didn't. but after loading:
hw.acpi.reset_video: 0
hw.acpi.video.lcd0.active: 0
hw.acpi.video.lcd0.brightness: 99
hw.acpi.video.lcd0.fullpower: 100
hw.acpi.video.lcd0.economy: 100
hw.acpi.video.lcd0.levels: 100 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 
66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 
91 92 93 94 95 96 97 98 99 100
dev.acpi_video.%parent:
dev.acpi_video.0.%desc: ACPI video extension
dev.acpi_video.0.%driver: acpi_video
dev.acpi_video.0.%location:
dev.acpi_video.0.%pnpinfo:
dev.acpi_video.0.%parent: vgapci0

no effect on keys. still doesn't work