| Message ID | 20240901050035.1739935-1-superm1@kernel.org |
|---|---|
| Headers | show |
| Series | amd-pstate: Better handling for systems without an MSR | expand |
On 9/1/2024 00:00, Mario Limonciello wrote: > From: Mario Limonciello <mario.limonciello@amd.com> > > This lets a system that supports the MSR run in shared memory mode > instead to help replicate and debug issues. > > Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> After some offline discussion, will drop this patch. Second patch will remain and I will queue it up for -next. > --- > .../admin-guide/kernel-parameters.txt | 5 +++ > Documentation/admin-guide/pm/amd-pstate.rst | 5 +++ > drivers/cpufreq/amd-pstate.c | 32 +++++++++++++------ > 3 files changed, 32 insertions(+), 10 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 09126bb8cc9ff..041c609ed50ea 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -383,6 +383,11 @@ > disable > Disable amd-pstate preferred core. > > + amd_pstate_msr= > + [X86] > + disable > + Disable amd-pstate CPPC MSR (force shared memory). > + > amijoy.map= [HW,JOY] Amiga joystick support > Map of devices attached to JOY0DAT and JOY1DAT > Format: <a>,<b> > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst > index d0324d44f5482..b06632556102e 100644 > --- a/Documentation/admin-guide/pm/amd-pstate.rst > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > @@ -411,6 +411,11 @@ For systems that support ``amd-pstate`` preferred core, the core rankings will > always be advertised by the platform. But OS can choose to ignore that via the > kernel parameter ``amd_prefcore=disable``. > > +``amd_pstate_msr=disable`` > + > +For systems that support a dedicated CPPC MSR, ignore it's use and run > +with shared memory instead. > + > User Space Interface in ``sysfs`` - General > =========================================== > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 93adde45bebce..89438a3654002 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -88,6 +88,7 @@ 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 bool amd_pstate_msr = true; > static struct quirk_entry *quirks; > > /* > @@ -187,7 +188,7 @@ static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64 cppc_req_cached) > u64 epp; > int ret; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > if (!cppc_req_cached) { > epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, > &cppc_req_cached); > @@ -260,7 +261,7 @@ static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp) > int ret; > struct cppc_perf_ctrls perf_ctrls; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > u64 value = READ_ONCE(cpudata->cppc_req_cached); > > value &= ~GENMASK_ULL(31, 24); > @@ -813,7 +814,7 @@ static int amd_pstate_get_highest_perf(int cpu, u32 *highest_perf) > { > int ret; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > u64 cap1; > > ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1); > @@ -1058,7 +1059,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) > /* It will be updated by governor */ > policy->cur = policy->cpuinfo.min_freq; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) > + if (amd_pstate_msr) > policy->fast_switch_possible = true; > > ret = freq_qos_add_request(&policy->constraints, &cpudata->req[0], > @@ -1288,7 +1289,7 @@ static int amd_pstate_change_mode_without_dvr_change(int mode) > > cppc_state = mode; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC) || cppc_state == AMD_PSTATE_ACTIVE) > + if (amd_pstate_msr || cppc_state == AMD_PSTATE_ACTIVE) > return 0; > > for_each_present_cpu(cpu) { > @@ -1524,7 +1525,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) > else > policy->policy = CPUFREQ_POLICY_POWERSAVE; > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value); > if (ret) > return ret; > @@ -1612,7 +1613,7 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy) > epp = 0; > > /* Set initial EPP value */ > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > value &= ~GENMASK_ULL(31, 24); > value |= (u64)epp << 24; > } > @@ -1657,7 +1658,7 @@ static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata) > value = READ_ONCE(cpudata->cppc_req_cached); > max_perf = READ_ONCE(cpudata->highest_perf); > > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value); > } else { > perf_ctrls.max_perf = max_perf; > @@ -1691,7 +1692,7 @@ static void amd_pstate_epp_offline(struct cpufreq_policy *policy) > value = READ_ONCE(cpudata->cppc_req_cached); > > mutex_lock(&amd_pstate_limits_lock); > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) { > cpudata->epp_policy = CPUFREQ_POLICY_UNKNOWN; > > /* Set max perf same as min perf */ > @@ -1936,7 +1937,9 @@ static int __init amd_pstate_init(void) > } > > /* capability check */ > - if (cpu_feature_enabled(X86_FEATURE_CPPC)) { > + if (amd_pstate_msr) > + amd_pstate_msr = cpu_feature_enabled(X86_FEATURE_CPPC); > + if (amd_pstate_msr) { > pr_debug("AMD CPPC MSR based functionality is supported\n"); > if (cppc_state != AMD_PSTATE_ACTIVE) > current_pstate_driver->adjust_perf = amd_pstate_adjust_perf; > @@ -2002,8 +2005,17 @@ static int __init amd_prefcore_param(char *str) > return 0; > } > > +static int __init amd_msr_param(char *str) > +{ > + if (!strcmp(str, "disable")) > + amd_pstate_msr = false; > + > + return 0; > +} > + > early_param("amd_pstate", amd_pstate_param); > early_param("amd_prefcore", amd_prefcore_param); > +early_param("amd_pstate_msr", amd_msr_param); > > MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>"); > MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
From: Mario Limonciello <mario.limonciello@amd.com> Since the policy changed for amd-pstate to enable on systems with shared memory designs by default too some users have reported that software like power-profiles-daemon fails with an error -524. This happens because error codes from the CPPC API are ignored during the initial setup so all the sysfs files are created but don't work. This series does two things: 1. Add a debugging early param to force going into shared memory mode even on a system with a dedicated MSR. This will aid in debugging reported issues. 2. Catch errors in amd_pstate_epp_update_limit() and pass them up. If any errors occurred with CPPC API then amd-pstate won't be setup. Mario Limonciello (2): cpufreq/amd-pstate: Add an early param to disable MSR mode cpufreq/amd-pstate: Catch failures for amd_pstate_epp_update_limit() .../admin-guide/kernel-parameters.txt | 5 ++- Documentation/admin-guide/pm/amd-pstate.rst | 5 +++ drivers/cpufreq/amd-pstate.c | 43 +++++++++++++------ 3 files changed, 38 insertions(+), 15 deletions(-)