Date: Sat, 10 May 2014 15:43:46 -0400 From: Henry Hu <henry.hu.sh@gmail.com> To: =?UTF-8?B?WMSrY8Oy?= <xico@atelo.org> Cc: "freebsd-x11@freebsd.org" <freebsd-x11@freebsd.org> Subject: Re: Intel i915 backlight Message-ID: <CAEJt7hacm16LKu08pBVBAxcfM23Y1F2Ra=F7_8w0k-bg4_Uy8A@mail.gmail.com> In-Reply-To: <20140509221926.GA2342@coyotlan.atelo.org> References: <20140509221926.GA2342@coyotlan.atelo.org>
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On Fri, May 9, 2014 at 6:19 PM, X=C4=ABc=C3=B2 <xico@atelo.org> wrote: > Dear freebsd-x11, > > I am running /stable/10 (with i915kms and newcons) on a Vaio VPCZ21 > with a SandyBridge. Unfortunately backlight is not working out of the > box. > > I played a bit with the existing acpi modules (including acpi_sony and > acpi_video), and wrote a bit of code to modify the backlight level, > through sony acpi, but it does not seem quite effective. Basically, the > (sony) acpi reports 16 backlight levels, iirc, but modifying them does > not influence the actual brightness. > > On linux, backlight level is controlled through the graphic card. So, > basically I am investigating how to do so on FreeBSD. I am quite unsure > of how it works, probably xbacklight relies on xf86-video-intel. There > is some code in sys/dev/drm2/i915/intel_panel.c which looks appropriate > to handle the backlight, but I fail to understand how it is called by > xorg, for instance. > > Well, I assume someone here will have a better understanding of all > that, and possible on how the intel backlight works, and whether it is > only a pwm. For now, I am relying on software xrandr --brightness to set > an adequate luminosity, before further investigating the issue. > I'm using an ASUS UX51VZ, with an integrated intel display adapter, and a NVidia card. Now I'm using intel-backlight tool from intel-gpu-tools ( http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/). It works fairly well. There are several ACPI functions which seem to set the brightness, but most of them don't work, including \_SB.ATKD.SPLV. Settings in sysctls hw.acpi.video do not work for me, although I can see brightness levels being reported. I think that some code is absent in the i915 module, because in sys/dev/drm2/i915/intel_opregion.c, there is a big block of code surrounded by #ifdef CONFIG_ACPI which only works for Linux. I've seen a patch which exposed some sysctls to adjust brightness, and it calls intel_panel_set_backlight()/intel_panel_get_max_backlight(). > Best, > > -- > X=C4=ABc=C3=B2 > _______________________________________________ > freebsd-x11@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-x11 > To unsubscribe, send any mail to "freebsd-x11-unsubscribe@freebsd.org" --=20 Cheers, Henry
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