cpufreq/amd-pstate: Loosen requirement on lowest nonlinear frequency != min freq

[PATCH] cpufreq/amd-pstate: Loosen requirement on lowest nonlinear frequency != min freq

Posted by Mario Limonciello 1 week, 2 days ago

This requirement was introduced by commit 8f8b42c1fcc93 ("cpufreq:
amd-pstate: optimize the initial frequency values verification")
specifically to aid in debugging BIOS issues with invalid _CPC tables
on some older systems.

This requirement is too tight for new systems though as some systems
actually have lowest nonlinear frequency identical to minimum
frequency.  Allow that combo to work.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index a74a4cf99d22e..3d72337a33369 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1031,7 +1031,7 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
 		return -EINVAL;
 	}
 
-	if (lowest_nonlinear_freq <= min_freq || lowest_nonlinear_freq > nominal_freq) {
+	if (lowest_nonlinear_freq < min_freq || lowest_nonlinear_freq > nominal_freq) {
 		pr_err("lowest_nonlinear_freq(%d) value is out of range [min_freq(%d), nominal_freq(%d)]\n",
 			lowest_nonlinear_freq, min_freq, nominal_freq);
 		return -EINVAL;
-- 
2.43.0

Re: [PATCH] cpufreq/amd-pstate: Loosen requirement on lowest nonlinear frequency != min freq

Posted by K Prateek Nayak 4 days, 13 hours ago

Hello Mario,

On 7/15/2026 11:13 PM, Mario Limonciello wrote:
> This requirement was introduced by commit 8f8b42c1fcc93 ("cpufreq:
> amd-pstate: optimize the initial frequency values verification")
> specifically to aid in debugging BIOS issues with invalid _CPC tables
> on some older systems.
> 
> This requirement is too tight for new systems though as some systems
> actually have lowest nonlinear frequency identical to minimum
> frequency.  Allow that combo to work.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Since I've not seen anyone complain about this on servers, and neither did
any of the machine I ran this on, feel free to include:

Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>

The "<" check should be good enough to catch any borken BIOS.

> ---
>  drivers/cpufreq/amd-pstate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index a74a4cf99d22e..3d72337a33369 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1031,7 +1031,7 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
>  		return -EINVAL;
>  	}
>  
> -	if (lowest_nonlinear_freq <= min_freq || lowest_nonlinear_freq > nominal_freq) {
> +	if (lowest_nonlinear_freq < min_freq || lowest_nonlinear_freq > nominal_freq) {
>  		pr_err("lowest_nonlinear_freq(%d) value is out of range [min_freq(%d), nominal_freq(%d)]\n",
>  			lowest_nonlinear_freq, min_freq, nominal_freq);
>  		return -EINVAL;

-- 
Thanks and Regards,
Prateek