From 47d4e945dff8139050473be4ab263a32e1da910c Mon Sep 17 00:00:00 2001 From: Christian Loehle Date: Fri, 24 Jul 2026 11:40:42 +0100 Subject: [PATCH] ACPI: CPPC: Skip writes to unsupported performance controls MIN_PERF and MAX_PERF are optional CPPC controls. DESIRED_PERF is also optional with CPPC2 when autonomous selection is supported. The cppc-cpufreq target callbacks populate both limits for every request without checking whether the controls are implemented. cppc_set_perf() consequently passes NULL register descriptors to cpc_write(). The writes fail width validation and their return values are ignored, so the failed access paths are repeated on every target request. An autonomous-only platform can take the same path for DESIRED_PERF. Check that each performance control is supported before calling cpc_write(). Fixes: ea3db45ae476 ("cpufreq: cppc: Update MIN_PERF/MAX_PERF in target callbacks") Reviewed-by: Sumit Gupta Signed-off-by: Christian Loehle Reviewed-by: Lifeng Zheng Link: https://patch.msgid.link/20260724104042.1481804-1-christian.loehle@arm.com Signed-off-by: Rafael J. Wysocki --- drivers/acpi/cppc_acpi.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 1d3a94100491..53d09ca98f06 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1963,16 +1963,17 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) cpc_desc->write_cmd_status = 0; } - cpc_write(cpu, desired_reg, perf_ctrls->desired_perf); + if (CPC_SUPPORTED(desired_reg)) + cpc_write(cpu, desired_reg, perf_ctrls->desired_perf); /* * Only write if min_perf and max_perf not zero. Some drivers pass zero * value to min and max perf, but they don't mean to set the zero value, * they just don't want to write to those registers. */ - if (perf_ctrls->min_perf) + if (perf_ctrls->min_perf && CPC_SUPPORTED(min_perf_reg)) cpc_write(cpu, min_perf_reg, perf_ctrls->min_perf); - if (perf_ctrls->max_perf) + if (perf_ctrls->max_perf && CPC_SUPPORTED(max_perf_reg)) cpc_write(cpu, max_perf_reg, perf_ctrls->max_perf); if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(min_perf_reg) || CPC_IN_PCC(max_perf_reg))