Messages in this thread | | | Date | Wed, 31 Jan 2024 15:59:32 -0600 | Subject | Re: [PATCH 6/6] cpufreq:amd-pstate: add quirk for the pstate CPPC capabilities missing | From | Mario Limonciello <> |
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On 1/31/2024 02:50, 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
s/quick/quirk/
> issues fixed with correct workaround values to make pstate driver
to allow the 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 | 51 +++++++++++++++++++++++++++++++----- > include/linux/amd-pstate.h | 6 +++++ > 2 files changed, 51 insertions(+), 6 deletions(-) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index eea2e192d748..cbc415af0f08 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -64,6 +64,7 @@ static struct cpufreq_driver amd_pstate_driver; > static struct cpufreq_driver amd_pstate_epp_driver; > static int cppc_state = AMD_PSTATE_UNDEFINED; > static bool cppc_enabled; > +static struct quirk_entry *quirks; > > /** > * struct global_params - Global parameters, mostly tunable via sysfs. > @@ -121,6 +122,32 @@ 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; > +
Under the presumption that the quirk list will grow as more buggy older machines are identified, maybe it's worth having a dyndbg or info statement here to indicate that it's using quirked values for 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"),
This is way too specific isn't it? It would only load on that single system I would expect. But I think you want to have an entry that matches the DMI_PRODUCT_NAME or DMI_FAMILY_NAME instead most likely.
> + }, > + .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; > @@ -581,13 +608,19 @@ 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) > @@ -619,13 +652,14 @@ 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;
I think this hunk should be earlier in your series. Conceptually it seems to match what patch 3 does to me.
> + if (quirks && quirks->nominal_freq) > + nominal_freq = quirks->nominal_freq; > + else > + nominal_freq = READ_ONCE(cpudata->nominal_freq); > > - return cppc_perf.nominal_freq; > + return nominal_freq; > } > > static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata) > @@ -1623,6 +1657,11 @@ 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 446394f84606..ea80f961607d 100644 > --- a/include/linux/amd-pstate.h > +++ b/include/linux/amd-pstate.h > @@ -110,4 +110,10 @@ 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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