[Letux-kernel] Keyboard backlight on 5.10

[David Shah]

Hi,

I've noticed that the keyboard backlight was no longer working on
letux-5.10.y. The LCD backlight is fine, which pointed to a problem
with l4-abe in particular. The pertinent error is

[    2.649385] omap-dmtimer-pwm dmtimer-pwm at 8: Unable to find Timer
pdev

which unfortunately isn't that helpful. Looking at the changes, I found
this commit

 ARM: dts: Configure omap4 and 5 l4_abe for genpd and drop platform
data 
0fd1594b3c339f17210c7ebfff102ad054cfcc7d

which seems to be the problem as after changing l4_abe back from
simple-pm-bus to simple-bus; the keyboard backlight starts working
again.

I did notice that pyra_defconfig was missing CONFIG_SIMPLE_PM_BUS=y but
adding that to the config wasn't enough to make simple-pm-bus work so
there must be something else going on as well.

Any thoughts?

David