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    SubjectRE: [PATCH v2 6/6] cpufreq:amd-pstate: add quirk for the pstate CPPC capabilities missing
    Date
    [AMD Official Use Only - General]

    Hi Mario,

    > -----Original Message-----
    > From: Limonciello, Mario <Mario.Limonciello@amd.com>
    > Sent: Friday, February 2, 2024 11:17 PM
    > To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com;
    > viresh.kumar@linaro.org; Huang, Ray <Ray.Huang@amd.com>; Shenoy,
    > Gautham Ranjal <gautham.shenoy@amd.com>; Petkov, Borislav
    > <Borislav.Petkov@amd.com>
    > Cc: Deucher, Alexander <Alexander.Deucher@amd.com>; Huang, Shimmer
    > <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
    > Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux-
    > kernel@vger.kernel.org
    > Subject: Re: [PATCH v2 6/6] cpufreq:amd-pstate: add quirk for the pstate
    > CPPC capabilities missing
    >
    > On 2/2/2024 02:55, Perry Yuan wrote:
    > > Add quirk table to get CPPC capabilities issue fixed by providing
    > > correct perf or frequency values while driver loading.
    > >
    > > If CPPC capabilities are not defined in the ACPI tables or wrongly
    > > defined by platform firmware, it needs to use quick to get those
    > > issues fixed with correct workaround values to make pstate driver can
    > > be loaded even though there are CPPC capabilities errors.
    > >
    > > Signed-off-by: Perry Yuan <perry.yuan@amd.com>
    > > ---
    > > drivers/cpufreq/amd-pstate.c | 49
    > ++++++++++++++++++++++++++++++++++--
    > > include/linux/amd-pstate.h | 6 +++++
    > > 2 files changed, 53 insertions(+), 2 deletions(-)
    > >
    > > diff --git a/drivers/cpufreq/amd-pstate.c
    > > b/drivers/cpufreq/amd-pstate.c index 77effc3caf6c..4d426516abb9 100644
    > > --- a/drivers/cpufreq/amd-pstate.c
    > > +++ b/drivers/cpufreq/amd-pstate.c
    > > @@ -67,6 +67,7 @@ static struct cpufreq_driver amd_pstate_epp_driver;
    > > static int cppc_state = AMD_PSTATE_UNDEFINED;
    > > static bool cppc_enabled;
    > > static bool amd_pstate_prefcore = true;
    > > +static struct quirk_entry *quirks;
    > >
    > > /*
    > > * AMD Energy Preference Performance (EPP) @@ -111,6 +112,33 @@
    > > static unsigned int epp_values[] = {
    > >
    > > typedef int (*cppc_mode_transition_fn)(int);
    > >
    > > +static struct quirk_entry quirk_amd_7k62 = {
    > > + .nominal_freq = 2600,
    > > + .lowest_freq = 550,
    > > +};
    > > +
    > > +static int __init dmi_matched(const struct dmi_system_id *dmi) {
    > > + quirks = dmi->driver_data;
    > > + pr_info("hardware type %s found\n", dmi->ident);
    > > +
    > > + return 1;
    > > +}
    > > +
    > > +static const struct dmi_system_id amd_pstate_quirks_table[] __initconst
    > = {
    > > + {
    > > + .callback = dmi_matched,
    > > + .ident = "AMD EPYC 7K62",
    > > + .matches = {
    > > + DMI_MATCH(DMI_PRODUCT_VERSION, "C1"),
    > > + DMI_MATCH(DMI_PRODUCT_SERIAL,
    > "FX19911000028")
    >
    > I saw your response to v1, but really this is too narrow for upstream.
    > It's literally applying to a SINGLE system.
    >
    > I feel the rest of the patch is fine, but we shouldn't be adding single system
    > quirks.

    How about change to match the BIOS version ?
    Actually, the issue should be impacting all the systems which have the same broken BIOS.

    Perry.


    >
    > > + },
    > > + .driver_data = &quirk_amd_7k62,
    > > + },
    > > + {}
    > > +};
    > > +MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);
    > > +
    > > static inline int get_mode_idx_from_str(const char *str, size_t size)
    > > {
    > > int i;
    > > @@ -600,13 +628,19 @@ static void amd_pstate_adjust_perf(unsigned int
    > cpu,
    > > static int amd_get_min_freq(struct amd_cpudata *cpudata)
    > > {
    > > struct cppc_perf_caps cppc_perf;
    > > + u32 lowest_freq;
    > >
    > > int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
    > > if (ret)
    > > return ret;
    > >
    > > + if (quirks && quirks->lowest_freq)
    > > + lowest_freq = quirks->lowest_freq;
    > > + else
    > > + lowest_freq = cppc_perf.lowest_freq;
    > > +
    > > /* Switch to khz */
    > > - return cppc_perf.lowest_freq * 1000;
    > > + return lowest_freq * 1000;
    > > }
    > >
    > > static int amd_get_max_freq(struct amd_cpudata *cpudata) @@ -635,12
    > > +669,18 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
    > > static int amd_get_nominal_freq(struct amd_cpudata *cpudata)
    > > {
    > > struct cppc_perf_caps cppc_perf;
    > > + u32 nominal_freq;
    > >
    > > int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
    > > if (ret)
    > > return ret;
    > >
    > > - return cppc_perf.nominal_freq;
    > > + if (quirks && quirks->nominal_freq)
    > > + nominal_freq = quirks->nominal_freq;
    > > + else
    > > + nominal_freq = cppc_perf.nominal_freq;
    > > +
    > > + return nominal_freq;
    > > }
    > >
    > > static int amd_get_lowest_nonlinear_freq(struct amd_cpudata
    > > *cpudata) @@ -1672,6 +1712,11 @@ static int __init amd_pstate_init(void)
    > > if (cpufreq_get_current_driver())
    > > return -EEXIST;
    > >
    > > + quirks = NULL;
    > > +
    > > + /* check if this machine need CPPC quirks */
    > > + dmi_check_system(amd_pstate_quirks_table);
    > > +
    > > switch (cppc_state) {
    > > case AMD_PSTATE_UNDEFINED:
    > > /* Disable on the following configs by default:
    > > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
    > > index d21838835abd..7b2cbb892fd9 100644
    > > --- a/include/linux/amd-pstate.h
    > > +++ b/include/linux/amd-pstate.h
    > > @@ -124,4 +124,10 @@ static const char * const
    > amd_pstate_mode_string[] = {
    > > [AMD_PSTATE_GUIDED] = "guided",
    > > NULL,
    > > };
    > > +
    > > +struct quirk_entry {
    > > + u32 nominal_freq;
    > > + u32 lowest_freq;
    > > +};
    > > +
    > > #endif /* _LINUX_AMD_PSTATE_H */

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