From: Penny Zheng Date: Mon, 14 Apr 2025 11:10:55 +0000 (+0200) Subject: xen/cpufreq: only set gov NULL when cpufreq_driver.setpolicy is NULL X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=7610180ff9e741bf1c29a9d0e9753e1ee818e0e4;p=xen.git xen/cpufreq: only set gov NULL when cpufreq_driver.setpolicy is NULL amd-cppc on active mode bypasses the scaling governor layer, and provides its own P-state selection algorithms in hardware. Consequently, when it is used, the driver's -> setpolicy() callback is invoked to register per-CPU utilization update callbacks, not the ->target() callback. So, only when cpufreq_driver.setpolicy is NULL, we need to deliberately set old gov as NULL to trigger the according gov starting. Signed-off-by: Penny Zheng Reviewed-by: Jan Beulich --- diff --git a/xen/drivers/cpufreq/cpufreq.c b/xen/drivers/cpufreq/cpufreq.c index 4a103c6de9..19e2992335 100644 --- a/xen/drivers/cpufreq/cpufreq.c +++ b/xen/drivers/cpufreq/cpufreq.c @@ -307,7 +307,13 @@ int cpufreq_add_cpu(unsigned int cpu) if (hw_all || (cpumask_weight(cpufreq_dom->map) == perf->domain_info.num_processors)) { memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); - policy->governor = NULL; + + /* + * Only when cpufreq_driver.setpolicy == NULL, we need to deliberately + * set old gov as NULL to trigger the according gov starting. + */ + if ( cpufreq_driver.setpolicy == NULL ) + policy->governor = NULL; cpufreq_cmdline_common_para(&new_policy);