Hi, It needs the graphics driver work done. The backlight control is done by the driver on these chips, via acpi but not entirely implemented within acpi.
A On Jul 5, 2016 10:13 AM, "Marin Bernard" <li...@olivarim.com> wrote: > > > Hi, > > I just bought a Lenovo Thinkpad T450 laptop and installed FreeBSD on top > of it. It runs fine except I'm not able to change the display backlight. > The laptop embeds a Core i5-5300U CPU with an Intel Graphics 5500 adapter > (Broadwell). I know the adapter is not yet supported, but I hoped to have > backlight control working anyway! > > Backlight control is working fine with OpenBSD 5.9, Linux 4.1+ and > Windows, which is not very surprising as those OSes also support the > display adapter. It's not working on FreeBSD 10.3-RELEASE nor 11.0-ALPHA6. > > What I have tried: > - I tried to load acpi_ibm and acpi_video kernel modules and tweak the > sysctl they provide: I was able to modify the systctl values, but backlight > remained the same. > - I also tried to install graphics/intel-backlight. There again: I was > able to change values, but it didn't change the backlight. > - 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 just ignoring my adapter as it does not support it. > > I'm ready to cope with the VESA driver for some time but I'd really like > to get backlight control working. Do you have suggestions ? Is there > anything I can do to help ? > > I use the UEFI framebuffer with vt in graphics mode. I did not try to run > Xorg yet. Should I do it ? > > Thanks, > > --Marin > > > _______________________________________________ > freebsd-acpi@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-acpi > To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org" > _______________________________________________ freebsd-acpi@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-acpi To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org"