Date: Sun, 1 Feb 2015 21:52:47 +0100 From: "Ranjan1018 ." <214748mv@gmail.com> To: Elizabeth Myers <elizabeth@interlinked.me> Cc: Adrian Chadd <adrian@freebsd.org>, freebsd-current <freebsd-current@freebsd.org> Subject: Re: Questions on adding backlight support for the i915 driver Message-ID: <CACyC=qYdJ0j7erysNTBTBov9EOcv0ebA=hmjz-pm_ztPqbksrw@mail.gmail.com> In-Reply-To: <54CC5311.9070604@interlinked.me> References: <54C883E7.4000300@interlinked.me> <54CBA0A4.30708@FreeBSD.org> <54CC0999.90500@interlinked.me> <3595567.zVLW9tlg0N@ralph.baldwin.cx> <54CC2981.3040909@interlinked.me> <CAJ-VmokWhk4NEjkvzU-g4McA1d4=%2BBrFYgrzpLWUZ5yQawaKsQ@mail.gmail.com> <54CC5311.9070604@interlinked.me>
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> I have a sort of "rough draft" of this. I've tested all the percentages > (Ivy Bridge) and they do seem to correlate linearly (and to the > intel_backlight userland program used by a lot of people). I haven't > been able to test on any other hardware as I don't have it, and I don't > know what chipsets require the value to be inverted, so I've not > implemented that. > > If anyone else would like to help test, it'd be nice. > > Thank you Elizabeth for the patch. It works on my Samsung Ativ Book 2 with Ivy Bridge. I have modified the patch for 11-CURRENT and corrected these little bugs: 1) is possible to specify a percentage greater than 100% eg. with the command: =E2=80=98sysctl hw.dri.0.i915_backlight=3D111=E2=80= =99 is possible to set the hardware register above the maximum allowed. 2) the percentage values are truncated instead of rounded: if I set 10% with the intel_backlight program is reported as 9% with the command =E2=80=98sysctl hw.dri.0.i915_backlight=E2=80=99: # intel_backlight 10 current backlight value: 20% (976/4882) set backlight to 10% (488/4882) # sysctl hw.dri.0.i915_backlight hw.dri.0.i915_backlight: 9 but 488/4882 is more near to 10% than 9% I have tested the patch with: # uname -a FreeBSD ativ 11.0-CURRENT FreeBSD 11.0-CURRENT #10 r277961: Sat Jan 31 06:03:15 CET 2015 root@ativ:/usr/obj/usr/src/sys/GENERIC amd64 The patch is available at: http://pastebin.com/vKK7026H Regards, Maurizio
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