> Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
I can not say if brightness controls worked immediately after installing the system. However, they were definitely broken after installing a few standard packages and the (proprietary) graphics drivers. The latest upstream kernel does *not* resolve the issue (neither are the FN buttons working, nor are `backlight` classes available under `/sys/class/backlight`). (I guess "generic" was the proper variant to test?) $ uname -r 4.15.0-041500-generic $ dmesg | grep acpi [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x02] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x03] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x04] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x05] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x06] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x07] high edge lint[0x1]) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x08] high edge lint[0x1]) [ 0.045039] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 [ 0.104918] acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI] [ 0.105102] acpi PNP0A08:00: _OSC: platform does not support [PCIeHotplug PME AER PCIeCapability] [ 0.105105] acpi PNP0A08:00: _OSC: not requesting control; platform does not support [PCIeCapability] [ 0.105109] acpi PNP0A08:00: _OSC: OS requested [PCIeHotplug PME AER PCIeCapability] [ 0.105112] acpi PNP0A08:00: _OSC: platform willing to grant [] [ 0.105114] acpi PNP0A08:00: _OSC failed (AE_SUPPORT); disabling ASPM [ 0.264669] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024 ns [ 1.541604] acpi device:77: hash matches [ 1.542026] acpi device:4a: hash matches [ 14.000879] acpi PNP0C14:02: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on PNP0C14:01) [ 14.000963] acpi PNP0C14:03: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on PNP0C14:01) [ 14.075152] thinkpad_acpi: ThinkPad ACPI Extras v0.25 [ 14.075153] thinkpad_acpi: http://ibm-acpi.sf.net/ [ 14.075154] thinkpad_acpi: ThinkPad BIOS N1UET37W (1.11 ), EC unknown [ 14.075155] thinkpad_acpi: Lenovo ThinkPad P51, model 20HJS27B00 [ 14.440734] thinkpad_acpi: radio switch found; radios are enabled [ 14.639622] thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio is unblocked [ 14.650775] input: ThinkPad Extra Buttons as /devices/platform/thinkpad_acpi/input/input13 ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1747273 Title: Can not control brightness on Thinkpad P51 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1747273/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
