Re: drm2 regression: backlight adjustment on ivybridge no longer works

On 1. Februar 2015 11:20:26 MEZ, Alexandr Krivulya <shuriku_at_shurik.kiev.ua> wrote:
>01.02.2015 12:12, Lars Engels пишет:
>> On Sun, Feb 01, 2015 at 10:41:25AM +0100, Lars Engels wrote:
>>> On Sun, Feb 01, 2015 at 03:35:15AM -0600, Andrew Wilcox wrote:
>>>> Lars Engels sent: 01 February 2015 03:18:
>>>>> With acpi_video I get some interesting sysctl:
>>>>> 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
>>>>>
>>>>> I guess it should not be 100 100 0 ... 100?
>>>> Actually, the "standard" internal ACPI brightness level struct
>(BRTN in the DSDT) is laid out as:
>>>>
>>>> * "Full power" value (one byte, the value at which the brightness
>should be set on AC by default)
>>>> * "Economy" value (one byte, the value at which the brightness
>should be set on battery by default)
>>>> * Actual values (N bytes, up to Max but frequently not)
>>>>
>>>> So, no, that value indeed sounds correct.  On my laptop the value
>is:
>>>> 80 47 0 7 13 20 27 33 40 47 53 60 67 73 80 87 93 100
>>> Thank you for the explanation.
>>> FWIW, here is the full output from sysctl hw.acpi.video.lcd0:
>>>
>>> hw.acpi.video.lcd0.active: 1
>>> hw.acpi.video.lcd0.brightness: 11
>>> 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
>>> hw.acpi.video.crt0.active: 1
>>> hw.acpi.video.ext0.active: 1
>>> hw.acpi.video.ext1.active: 1
>>> hw.acpi.video.ext2.active: 1
>>> hw.acpi.video.ext3.active: 1
>>> hw.acpi.video.ext4.active: 1
>>> hw.acpi.video.ext5.active: 1
>>>
>>>> What revision of -CURRENT are you running?  What is the outcome of
>>>> trying the patch posted Saturday morning (UTC) from Elizabeth Myers
>>>> (message ID <54CC5311.9070604_at_interlinked.me>)?
>>>>
>>> I'm currently running r277858 and haven't tried the patch, yet. But
>will
>>> do now and report back.
>>>
>> So now I have a new sysctl hw.dri.0.i915_backlight. But no matter
>what
>> value I pass to it, the brightness doesn't change.
>>
>> It's a Ivy Brigde notebook where drm shows some errors in dmesg.
>Please
>> see: http://pastie.org/9877917
>>
>>
>
>Please try to boot with acpi_ibm and without acpi_video. This way all
>works for me.

That‘s already what I do. Also tried it with acpi_video without luck.