Commit 26780131 authored by Stephan Gerhold's avatar Stephan Gerhold Committed by Greg Kroah-Hartman
Browse files

arm64: dts: qcom: msm8916: Add missing MDSS reset



commit 99b78773 upstream.

On most MSM8916 devices (aside from the DragonBoard 410c), the bootloader
already initializes the display to show the boot splash screen. In this
situation, MDSS is already configured and left running when starting Linux.
To avoid side effects from the bootloader configuration, the MDSS reset can
be specified in the device tree to start again with a clean hardware state.

The reset for MDSS is currently missing in msm8916.dtsi, which causes
errors when the MDSS driver tries to re-initialize the registers:

 dsi_err_worker: status=6
 dsi_err_worker: status=6
 dsi_err_worker: status=6
 ...

It turns out that we have always indirectly worked around this by building
the MDSS driver as a module. Before v6.17, the power domain was temporarily
turned off until the module was loaded, long enough to clear the register
contents. In v6.17, power domains are not turned off during boot until
sync_state() happens, so this is no longer working. Even before v6.17 this
resulted in broken behavior, but notably only when the MDSS driver was
built-in instead of a module.

Cc: stable@vger.kernel.org
Fixes: 305410ff ("arm64: dts: msm8916: Add display support")
Signed-off-by: default avatarStephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: default avatarKonrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250915-msm8916-resets-v1-1-a5c705df0c45@linaro.org


Signed-off-by: default avatarBjorn Andersson <andersson@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3a0f197d
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