Hello,
On Sat, May 24, 2025 at 12:31:13PM +0200, Fejes Ferenc wrote:
> The simplest workaround I found is to include "clk_ignore_unused" in the kernel
> parameters when the installer boots.
>
> This also works with GRUB, there press "e" key when GRUB menu appears, edit the
> line starts with "linux" e.g.:
>
> linux /boot/vmlinuz clk_ignore_unused ro quiet
>
> Since the clock driver kernel modules included in the arm64 installer initrd.gz,
> it can load it successfully.
I'd like to understand that issue but don't have an affected machine. So
maybe you can do the following:
Compile a kernel with CLOCK_ALLOW_WRITE_DEBUGFS defined in
drivers/clk/clk.c and boot that with clk_ignore_unused on the cmdline
and then disable all the clocks that are kept running one after another
using:
echo 1 > /sys/kernel/debug/clk/${CLK}/clk_prepare_enable
echo 0 > /sys/kernel/debug/clk/${CLK}/clk_prepare_enable
(The clock must first be explicitly enabled to make disabling actually
do something.)
Some time ago I experienced (but didn't debug) that a rockchip based
machine failed to boot with a clk problem when the console was setup on
the kernel commands (i.e. console=ttyS0) while it booted fine when the
default console was just setup via dt. Maybe that's something to check
on Mediatek, too?
Best regards
Uwe
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