linuxmsm/laptops-kernel
0
0
Fork 0
mirror of https://github.com/linux-msm/laptops-kernel.git synced 2026-08-13 14:19:53 -07:00
Code Issues Packages Projects Releases Wiki Activity

ACPI: CPPC: Skip writes to unsupported performance controls

Browse Source 
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: ea3db45ae4 ("cpufreq: cppc: Update MIN_PERF/MAX_PERF in target callbacks")
Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20260724104042.1481804-1-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Christian Loehle
2026-07-27 15:18:50 +02:00
committed by Rafael J. Wysocki
parent 601eecdeee
commit 47d4e945df
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/acpi/cppc_acpi.c
+4 -3
View File
@@ -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))