Date: Tue, 05 Jul 2016 16:07:44 +0200 From: "Marin Bernard" <lists@olivarim.com> To: freebsd-acpi@freebsd.org Subject: Thinkpad T450: can't change display backlight Message-ID: <1467727664-c61d10674bafe6227cdc75f523f047ad@olivarim.com>
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=20 Hi, =20 =20 I just=A0bought a Lenovo Thinkpad T450 laptop and installed FreeBSD on top of= it. It runs fine except I'm not able to=A0change=A0the display backlight. Th= e laptop embeds a Core i5-5300U CPU=A0with an=A0Intel Graphics 5500 adapter (= Broadwell). I know the adapter is not yet supported, but I hoped to=A0have ba= cklight control working anyway! =20 =20 Backlight control is working fine=A0with OpenBSD 5.9, Linux 4.1+ and Windows,= which is not very surprising as those OSes also support the display adapter.= =A0It's not working on=A0FreeBSD 10.3-RELEASE nor 11.0-ALPHA6. =20 =20 What I have tried: =20 =A0 - I tried to load acpi_ibm and acpi_video kernel modules and tweak=A0the= =20sysctl they provide: I was able to modify the systctl values, but=A0backli= ght remained the same. =20 =A0 - I also tried to install graphics/intel-backlight. There again: I was ab= le to change values, but it didn't change the backlight. =20 =A0 - I tried to load the i915kms intel modul, just in case backlight control= needed this to work properly. As before, no effect. I think the module is ju= st ignoring my adapter as it does not support it. =20 =20 I'm ready to cope with the=A0VESA driver for some time but I'd really like to= get=A0backlight control working. Do you have suggestions ? Is there anything= I can do to help ? =20 =20 I use the UEFI framebuffer with vt in graphics mode. I did not try to run Xor= g yet. Should I=A0do it ? =20 =20 Thanks, =20 =20 --Marin =20 =20
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