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Commitcac173bea5("ACPI: processor: idle: Rework the handling of acpi_processor_ffh_lpi_probe()") moved the acpi_processor_ffh_lpi_probe() call from acpi_processor_setup_cpuidle_dev(), where its return value was ignored, to acpi_processor_get_power_info(), where it is now treated as a hard failure. As a result, platforms where psci_acpi_cpu_init_idle() returned -ENODEV stopped registering any cpuidle states, forcing CPUs to busy-poll when idle. On NVIDIA Grace (aarch64) systems with PSCIv1.1, pr->power.count is 1 (only WFI, no deep PSCI states beyond it), so the previous "count = pr->power.count - 1; if (count <= 0) return -ENODEV;" check returned -ENODEV for all 72 CPUs and disabled cpuidle entirely. The lpi_states count is already validated in acpi_processor_get_lpi_info(), so the check here is redundant. Simplify the loop to iterate over lpi_states[1..power.count). When only WFI is present, the loop body simply does not execute and the function returns 0, which is the correct outcome: there is nothing to validate for FFH and no error to report. Suggested-by: Huisong Li <lihuisong@huawei.com> Cc: stable@vger.kernel.org Fixes:cac173bea5("ACPI: processor: idle: Rework the handling of acpi_processor_ffh_lpi_probe()") Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>