Re: linux-6.6.y: Regression in amd-pstate cpufreq driver since 6.6.34

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Jul 02, 2024 at 11:15:14AM +0200, Greg Kroah-Hartman wrote:
> On Mon, Jul 01, 2024 at 04:53:20PM -0500, Mario Limonciello wrote:
> > On 7/1/2024 11:13, Lars Wendler wrote:
> > > Hello Mario,
> > > 
> > > Am Mon, 1 Jul 2024 10:58:17 -0500
> > > schrieb Mario Limonciello <mario.limonciello@amd.com>:
> > > 
> > > > > I've tested both, 6.9.7 and 6.10-rc6 and they both don't have that
> > > > > issue. I can disable CPU boost with both kernel versions.
> > > > 
> > > > Thanks for checking those.  That's good to hear it's only an issue in
> > > > the LTS series.
> > > > 
> > > > It means we have the option to either drop that patch from LTS kernel
> > > > series or identify the other commit(s) that helped it.
> > > > 
> > > > Can you see if adding this commit to 6.6.y helps you?
> > > > 
> > > > https://git.kernel.org/superm1/c/8164f743326404fbe00a721a12efd86b2a8d74d2
> > > 
> > > that commit does not fix the regression.
> > > 
> > 
> > I think I might have found the issue.
> > 
> > With that commit backported on 6.6.y in amd_pstate_set_boost() the policy
> > max frequency is nominal  *1000 [1].
> > 
> > However amd_get_nominal_freq() already returns nominal *1000 [2].
> > 
> > If you compare on 6.9 get_nominal_freq() doesn't return * 1000 [3].
> > 
> > So the patch only makes sense on 6.9 and later.
> > 
> > We should revert it in 6.6.y.
> > 
> > 
> > 
> > Greg,
> > 
> > 
> > Can you please revert 8f893e52b9e0 ("cpufreq: amd-pstate: Fix the
> > inconsistency in max frequency units") in 6.6.y?
> 
> Sure, but why only 6.6.y?  What about 6.1.y, should it be reverted from
> there as well?

And have now done so.