ThinkPad T14 Gen 1 AMD switching to lowest brightness during boot process with 5.14-rc2

Alex Deucher alexdeucher at
Thu Jul 22 17:26:26 UTC 2021

On Thu, Jul 22, 2021 at 10:04 AM Martin Steigerwald <martin at> wrote:
> Not subscribed, so please Cc on answer.
> Hi!
> Just compiled 5.14-rc2 for my T14 Gen 1 AMD with "AMD Ryzen 7 PRO 4750U
> with Radeon Graphics" with Low Power Display (400 Nits).
> Using that kernel, the display starts with the usual high brightness.
> However, during boot the brightness goes down to what appears to be the
> minimum. In KDE Plasma however the brightness of the display is shown as
> maximum.
> If I move around the brightness slider just a few percent down from 100
> to maybe 98% or something like that the brightness is immediately reset
> to its actual value display by the slider.
> This did not happen with 5.13.

Please file a ticket here:
Can you bisect?


> I am still on X11 as some KDE Plasma features are not yet available for
> Wayland.
> This is on Devuan Ceres – basically Debian Sid without Systemd – with
> Runit as init system, so there no automatic Systemd brightness logic
> should be involved.
> If attached kernel configuration is stripped, please let me know.
> Best,
> --
> Martin_______________________________________________
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> amd-gfx at

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