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Date:      Tue, 9 Feb 2021 21:31:30 -0800
From:      Kevin Oberman <>
To:        "" <>
Subject:   Brightness cannot be set on Lenovo L15 ThinkPad
Message-ID:  <>

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I can only guess that this may be an ACPI issue.

I recently (last week) replaced my decade old T520 with a new ThinkPad L15
with a 10th gen I5 CPU (Tiger Lake). I have everything working except the
WiFi (which I knew would not work) and setting brightness on the display.

I have loaded acpi_ibm and it returns '0' for brightness. I tried
intel-backlight, which shows the brightness to be '0'. It does nothing,

I thought that I read that drm-fbsd13-kmod had the ability to do the job,
but I have no idea how to do anything with it. I do see sysctls for
hw.i915kms.enable_dpcd_backlight and invert_brightness, but I still have no
clue whether they are relevant.

Any suggestions would be greatly appreciated!
Kevin Oberman, Part time kid herder and retired Network Engineer
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683

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