On Tue, Apr 28, 2026 at 01:18:11PM +0100, James Clark wrote:
ETE registers are always system registers so it's highly unlikely there will be an implementation that preserves them on CPU power down. Also the ETE DT binding never documented "arm,coresight-loses-context-with-cpu" so nobody would have legitimately been able to use that binding to fix it.
Fix it by hard coding the setting for ETE and add a warning if the user tried to use the module parameter. Don't add a warning if loses-context-with-cpu is present in the DT as it's not a documented binding anyway. etm4_init_pm_save() needs to happen after drvdata is initialised so etm4x_is_ete() can be called.
This fixes the following error when using Coresight with ACPI on the FVP which supports CPU PM:
coresight ete0: External agent took claim tag WARNING: drivers/hwtracing/coresight/coresight-core.c:248 at coresight_disclaim_device_unlocked+0xe0/0xe8, CPU#0: perf/117
Fixes: 35e1c9163e02 ("coresight: ete: Add support for ETE tracing") Signed-off-by: James Clark james.clark@linaro.org
Reviewed-by: Leo Yan leo.yan@arm.com