Re: [PATCH 0/6] cpufreq/amd-pstate: Dynamic EPP fixes

[Mario Limonciello <mario.limonciello@amd.com>]

On 5/8/26 00:17, K Prateek Nayak wrote:
> Few rare race conditions were found when testing the Dynamic EPP feature
> on EPYC platforms:
> 
> o Toggling dynamic EPP is essentially a driver switch into the same mode
>    and can race with an admin-initiated driver switch which can cause the
>    system to hang.
> 
> o If a profile change / power supply status change races with the driver
>    unloading, it can overwrite the Floor Perf restored in the CPPC_REQ
>    register that was meant to be left untouched until the next driver
>    load.
> 
> o When dynamic mode is disabled, the default EPP hint is set based on
>    the power supply mode at the time of driver load which can cause the
>    battery to drain faster when starting off from AC supply and then
>    switching to battery.
> 
> When fixing and testing the above, a couple of incorrect error codes
> were noted which is also fixed in the series along with the unit test.
> 
> Series is based on mainline at v7.1-rc2 release tag. Thanks to Mario for
> initial review. Feedback is greatly appreciated.
> ---
> K Prateek Nayak (6):
>    cpufreq/amd-pstate: Grab "amd_pstate_driver_lock" when toggling
>      dynamic_epp
>    cpufreq/amd-pstate: Return -ENOMEM on failure to allocate profile_name
>    cpufreq/amd-pstate: Allow writes to dynamic_epp when state isn't
>      modified
>    cpufreq/amd-pstate: Reorder notifier unregistration and floor perf
>      reset
>    cpufreq/amd-pstate: Use "epp_default_dc" as default when dynamic_epp
>      is disabled
>    cpufreq/amd-pstate-ut: Drop policy reference before driver switch
> 
>   drivers/cpufreq/amd-pstate-ut.c | 36 ++++++++++++++++++++++++++-------
>   drivers/cpufreq/amd-pstate.c    | 23 ++++++++++++++++-----
>   2 files changed, 47 insertions(+), 12 deletions(-)
> 
> 
> base-commit: 7fd2df204f342fc17d1a0bfcd474b24232fb0f32

Much appreciated.  I've staged these in amd-pstate-fixes and will send 
out the PR next week after more testing.