On Thu, Apr 09, 2026 at 03:30:56PM +0100, James Clark wrote:
[...]
@@ -1759,16 +1760,36 @@ static int coresight_pm_check(struct coresight_path *path) if (source_has_cb) return 1; + sink_has_cb = coresight_ops(sink)->pm_save_disable && + coresight_ops(sink)->pm_restore_enable; + /* + * It is not permitted that the source has no callbacks while the sink + * does, as the sink cannot be disabled without disabling the source, + * which may lead to lockups. Alternatively, the ETM driver should + * enable self-hosted PM mode at probe (see etm4_probe()). + */ + if (sink_has_cb) { + pr_warn_once("coresight PM failed: source has no PM callbacks; " + "cannot safely control sink\n");
This prints out on my Orion board on a fresh boot because of how pm_save_enable is setup there. Do we really need the configuration of pm_save_enable for ETE/TRBE if we know that it always needs saving?
Yeah, I can remove this check and always bind CPU PM ops for ETE.
It also stops warning if I rmmod and modprobe the module after booting. Seems like pm_save_enable is different depending on how the module is loaded which doesn't seem right.
Thats because the warning is pr_warn_*once*()
I don't think so, I tested it with a printf instead of a warn once and also tested modprobeing straight after a reboot.
I am a bit surprised that Orion6 hits the CPU idle flow, as I observed that idle states are not enabled on my board:
# ls /sys/devices/system/cpu/cpu*/cpuidle ls: cannot access '/sys/devices/system/cpu/cpu*/cpuidle': No such file or directory
If you hit only once CPU idle notifier, it is good to add a dump_stack() in coresight_cpu_pm_notify and print the "cmd" argument, so we can know the calling coming from where. I am a bit suspect it might be a glitch in CPUIdle layer.
Thanks, Leo