To avoid some new AMD processors use wrong highest perf when amd pstate
driver loaded, this fix will query the highest perf from MSR register
MSR_AMD_CPPC_CAP1 and cppc_acpi interface firstly, then compare with the
highest perf value got by calling amd_get_highest_perf() function.
The lower value will be the correct highest perf we need to use.
Otherwise the CPU max MHz will be incorrect if the
amd_get_highest_perf() did not cover the new process family and model ID.
Like this lscpu info, the max frequency is incorrect.
Vendor ID: AuthenticAMD
Socket(s): 1
Stepping: 2
CPU max MHz: 5410.0000
CPU min MHz: 400.0000
BogoMIPS: 5600.54
Fixes: 3743d55b289c2 (x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations)
Signed-off-by: Perry Yuan <[email protected]>
---
drivers/cpufreq/amd-pstate.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9f4375f7ab46..f778ab37e436 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -354,6 +354,7 @@ static inline int amd_pstate_enable(bool enable)
static int pstate_init_perf(struct amd_cpudata *cpudata)
{
u64 cap1;
+ u32 highest_perf;
int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
&cap1);
@@ -365,7 +366,11 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
*
* CPPC entry doesn't indicate the highest performance in some ASICs.
*/
- WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
+ highest_perf = amd_get_highest_perf();
+ if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
+ highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
+
+ WRITE_ONCE(cpudata->highest_perf, highest_perf);
WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
@@ -377,12 +382,17 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
static int cppc_init_perf(struct amd_cpudata *cpudata)
{
struct cppc_perf_caps cppc_perf;
+ u32 highest_perf;
int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
if (ret)
return ret;
- WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
+ highest_perf = amd_get_highest_perf();
+ if (highest_perf > cppc_perf.highest_perf)
+ highest_perf = cppc_perf.nominal_perf;
+
+ WRITE_ONCE(cpudata->highest_perf, highest_perf);
WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
WRITE_ONCE(cpudata->lowest_nonlinear_perf,
--
2.34.1
On Sun, Aug 14, 2022 at 6:57 PM Perry Yuan <[email protected]> wrote:
>
> To avoid some new AMD processors use wrong highest perf when amd pstate
> driver loaded, this fix will query the highest perf from MSR register
> MSR_AMD_CPPC_CAP1 and cppc_acpi interface firstly, then compare with the
> highest perf value got by calling amd_get_highest_perf() function.
>
> The lower value will be the correct highest perf we need to use.
> Otherwise the CPU max MHz will be incorrect if the
> amd_get_highest_perf() did not cover the new process family and model ID.
>
> Like this lscpu info, the max frequency is incorrect.
>
> Vendor ID: AuthenticAMD
> Socket(s): 1
> Stepping: 2
> CPU max MHz: 5410.0000
> CPU min MHz: 400.0000
> BogoMIPS: 5600.54
>
> Fixes: 3743d55b289c2 (x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations)
> Signed-off-by: Perry Yuan <[email protected]>
This needs to be reviewed by the AMD P-state driver maintainer.
> ---
> drivers/cpufreq/amd-pstate.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9f4375f7ab46..f778ab37e436 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -354,6 +354,7 @@ static inline int amd_pstate_enable(bool enable)
> static int pstate_init_perf(struct amd_cpudata *cpudata)
> {
> u64 cap1;
> + u32 highest_perf;
>
> int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> &cap1);
> @@ -365,7 +366,11 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
> *
> * CPPC entry doesn't indicate the highest performance in some ASICs.
> */
> - WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
> + highest_perf = amd_get_highest_perf();
> + if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
> + highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
> +
> + WRITE_ONCE(cpudata->highest_perf, highest_perf);
>
> WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
> WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
> @@ -377,12 +382,17 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
> static int cppc_init_perf(struct amd_cpudata *cpudata)
> {
> struct cppc_perf_caps cppc_perf;
> + u32 highest_perf;
>
> int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> if (ret)
> return ret;
>
> - WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
> + highest_perf = amd_get_highest_perf();
> + if (highest_perf > cppc_perf.highest_perf)
> + highest_perf = cppc_perf.nominal_perf;
> +
> + WRITE_ONCE(cpudata->highest_perf, highest_perf);
>
> WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
> WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> --
> 2.34.1
>
[AMD Official Use Only - General]
Hi Rafael,
> -----Original Message-----
> From: Rafael J. Wysocki <[email protected]>
> Sent: Thursday, August 25, 2022 7:59 PM
> To: Yuan, Perry <[email protected]>
> Cc: Rafael Wysocki <[email protected]>; Huang, Ray
> <[email protected]>; Viresh Kumar <[email protected]>; Sharma,
> Deepak <[email protected]>; Limonciello, Mario
> <[email protected]>; Fontenot, Nathan
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Su, Jinzhou (Joe) <[email protected]>;
> Huang, Shimmer <[email protected]>; Du, Xiaojian
> <[email protected]>; Meng, Li (Jassmine) <[email protected]>; Linux
> PM <[email protected]>; Linux Kernel Mailing List <linux-
> [email protected]>
> Subject: Re: [PATCH] cpufreq: amd_pstate: Fix initial highest_perf value
>
> [CAUTION: External Email]
>
> On Sun, Aug 14, 2022 at 6:57 PM Perry Yuan <[email protected]> wrote:
> >
> > To avoid some new AMD processors use wrong highest perf when amd
> > pstate driver loaded, this fix will query the highest perf from MSR
> > register
> > MSR_AMD_CPPC_CAP1 and cppc_acpi interface firstly, then compare with
> > the highest perf value got by calling amd_get_highest_perf() function.
> >
> > The lower value will be the correct highest perf we need to use.
> > Otherwise the CPU max MHz will be incorrect if the
> > amd_get_highest_perf() did not cover the new process family and model
> ID.
> >
> > Like this lscpu info, the max frequency is incorrect.
> >
> > Vendor ID: AuthenticAMD
> > Socket(s): 1
> > Stepping: 2
> > CPU max MHz: 5410.0000
> > CPU min MHz: 400.0000
> > BogoMIPS: 5600.54
> >
> > Fixes: 3743d55b289c2 (x86, sched: Fix the AMD CPPC maximum
> performance
> > value on certain AMD Ryzen generations)
> > Signed-off-by: Perry Yuan <[email protected]>
>
> This needs to be reviewed by the AMD P-state driver maintainer.
There is one small change for this patch , will send V2 for further review.
Perry.
>
> > ---
> > drivers/cpufreq/amd-pstate.c | 14 ++++++++++++--
> > 1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 9f4375f7ab46..f778ab37e436 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -354,6 +354,7 @@ static inline int amd_pstate_enable(bool enable)
> > static int pstate_init_perf(struct amd_cpudata *cpudata) {
> > u64 cap1;
> > + u32 highest_perf;
> >
> > int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> > &cap1); @@ -365,7 +366,11 @@
> > static int pstate_init_perf(struct amd_cpudata *cpudata)
> > *
> > * CPPC entry doesn't indicate the highest performance in some ASICs.
> > */
> > - WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
> > + highest_perf = amd_get_highest_perf();
> > + if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
> > + highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
> > +
> > + WRITE_ONCE(cpudata->highest_perf, highest_perf);
> >
> > WRITE_ONCE(cpudata->nominal_perf,
> AMD_CPPC_NOMINAL_PERF(cap1));
> > WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > AMD_CPPC_LOWNONLIN_PERF(cap1)); @@ -377,12 +382,17 @@ static int
> > pstate_init_perf(struct amd_cpudata *cpudata) static int
> > cppc_init_perf(struct amd_cpudata *cpudata) {
> > struct cppc_perf_caps cppc_perf;
> > + u32 highest_perf;
> >
> > int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> > if (ret)
> > return ret;
> >
> > - WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
> > + highest_perf = amd_get_highest_perf();
> > + if (highest_perf > cppc_perf.highest_perf)
> > + highest_perf = cppc_perf.nominal_perf;
> > +
> > + WRITE_ONCE(cpudata->highest_perf, highest_perf);
> >
> > WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
> > WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > --
> > 2.34.1
> >