Re: Bad commit backported on the v5.15.y branch ?

[Thorsten Leemhuis]

On 11.10.24 10:48, Joel GUITTET wrote:
> 
> I faced some issue related to scaling frequency on ZynqMP device
> using v5.15.167 kernel. As an exemple setting the scaling frequency
> below show it's not properly set:
> 
> cat /sys/devices/system/cpu/cpufreq/policy0/
> scaling_available_frequencies 299999 399999 599999 1199999
> 
> echo 399999 > /sys/devices/system/cpu/cpufreq/policy0/
> scaling_setspeed
> 
> cat /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq 399999
> 
> cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq 299999
> ====> Should be 399999
> 
> After analysis of this issue with the help of Xilinx, it appears
> that a commit was backported on the 5.15.y branch, but probably it
> should not, or not as is. The commit is
> 9117fc44fd3a9538261e530ba5a022dfc9519620 modifying drivers/clk/
> zynqmp/divider.c.

FWIW, that is 1fe15be1fb6135 ("drivers: clk: zynqmp: update divider
round rate logic") [v6.8-rc1].

> Is anybody reading this message able to answer why it was
> backported ?

Looks like because it fixes a bug. I CCed the original author and those
that handled the patch, maybe they can help us out and tell us what's
the best strategy forward here.

> The information I have until now is that it is intended
> recent kernel version. Dependencies for this modification is
> currently under clarification with Xilinx (maybe another commit to
> backport).
> 
> By the way, reverting this commit fix the issue shown above.
Does 6.12-rc work fine for you? Because if not, we should fix the
problem there.

Ciao, Thorsten