[i915] intel_backlight does not function - Lenovo X1 Yoga OLED
Submitted by Dan Sanders
Assigned to Intel GFX Bugs mailing list
Description
Created attachment 126688
Full dmesg output with drm.debug=0x1e log_buf_len=1M
On the OLED version of the Lenovo X1 Yoga, the intel_backlight device reports a range of 0 to 852, but its setting has no effect. (Perhaps not too surprising since this device technically has no backlight.) The display brightness is always (near?) maximum when Linux is booted.
The thinkpad_acpi module does no better at providing brightness controls.
The xrandr --brightness setting is a nearly-adequate workaround, but is occasionally reset while using X.org normally (I have not investigated the cause yet).
Attached logs are from an Ubuntu kernel-ppa image, stamped:
cod/tip/drm-intel-next/2016-09-20 (6e05f3d3b9298a56d6f1acb474a75cf14a17c31e)
The laptop display is attached to eDP1. There is a second display attached to DP1; I can provide logs without that if requested.
I was not able to create a vbios dump. ("Input/Output error")
Attachment 126688, "Full dmesg output with drm.debug=0x1e log_buf_len=1M":
dmesg.txt