Some RP1 clocks broken in 6.18
@njhollinghurst is already working on this.
Since Dec 17, 2025.
Assessment
This issue has not been assessed yet.
Description
Describe the bug
Raspberry Pi 5: VEC, DPI and Audio Out are all broken with rpi-6.18.y (worked with rpi-6.12.y).
Although the DPI driver messes with its clock setup, both VEC and DPI rely on DeviceTree to assign the correct clock rates and parents. They all now complain that they're unable to select the assigned parent, and seem to end up with wildly wrong frequencies.
I note that in clk-rp1.c, clk_audio_out no longer lists pll_audio_sec in its list of parents, which seems wrong. However, this does not explain why VEC would fail to assign pll_video_sec as a parent.
Steps to reproduce the behaviour
Raspberry Pi 5: enable either VEC or DPI, optionally with Audio Out, using a subset of:
dtoverlay=vc4-kms-v3d,composite
#dtoverlay=vc4-kms-vga666 # remove composite to test this
dtoverlay=audremap
See errors in dmesg; measure the output waveforms or time video fame rate using e.g. kmstest --flip=100.
Device (s)
Raspberry Pi 5
System
Raspberry Pi 5 Model B Rev 1.1
PRETTY_NAME="Debian GNU/Linux 13 (trixie)"
Linux raspberrypi 6.18.1-v8-16k+ #241 SMP PREEMPT Wed Dec 17 14:33:37 GMT 2025 aarch64 GNU/Linux
Local kernel build at commit e132677b390ea5d7d9c6b99ed1f082ac880022fd (HEAD -> rpi-6.18.y, origin/rpi-6.18.y) Fri Dec 12 19:41:23 2025 +0000
Logs
[ 4.150084] clk: failed to reparent clk_vec to pll_video_sec: -22
[ 4.150385] clk: couldn't set clk_vec clk rate to 108000000 (-22), current rate: 100000000
[ 4.219145] clk: failed to reparent clk_audio_out to pll_audio_sec: -22
Additional context
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