6.16-stable review patch. If anyone has any objections, please let me know.
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From: Peng Fan peng.fan@nxp.com
[ Upstream commit 9a0658d3991e6c82df87584b253454842f22f965 ]
Fix a race condition where a second suspend notification from another SCMI agent wakes the system before SCMI_SYSPOWER_IDLE is set, leading to ignored suspend requests. This is due to interrupts triggering early execution of `scmi_userspace_notifier()` before the SCMI state is updated.
To resolve this, set SCMI_SYSPOWER_IDLE earlier in the device resume path, prior to `thaw_processes()`. This ensures the SCMI state is correct when the notifier runs, allowing the system to suspend again as expected.
On some platforms using SCMI, SCP cannot distinguish between CPU idle and suspend since both result in cluster power-off. By explicitly setting the idle state early, the Linux SCMI agent can correctly re-suspend in response to external notifications.
Signed-off-by: Peng Fan peng.fan@nxp.com Message-Id: 20250704-scmi-pm-v2-2-9316cec2f9cc@nxp.com Signed-off-by: Sudeep Holla sudeep.holla@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../firmware/arm_scmi/scmi_power_control.c | 22 ++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/firmware/arm_scmi/scmi_power_control.c b/drivers/firmware/arm_scmi/scmi_power_control.c index 21f467a92942..ab0cee0d4bec 100644 --- a/drivers/firmware/arm_scmi/scmi_power_control.c +++ b/drivers/firmware/arm_scmi/scmi_power_control.c @@ -46,6 +46,7 @@ #include <linux/math.h> #include <linux/module.h> #include <linux/mutex.h> +#include <linux/pm.h> #include <linux/printk.h> #include <linux/reboot.h> #include <linux/scmi_protocol.h> @@ -324,12 +325,7 @@ static int scmi_userspace_notifier(struct notifier_block *nb,
static void scmi_suspend_work_func(struct work_struct *work) { - struct scmi_syspower_conf *sc = - container_of(work, struct scmi_syspower_conf, suspend_work); - pm_suspend(PM_SUSPEND_MEM); - - sc->state = SCMI_SYSPOWER_IDLE; }
static int scmi_syspower_probe(struct scmi_device *sdev) @@ -354,6 +350,7 @@ static int scmi_syspower_probe(struct scmi_device *sdev) sc->required_transition = SCMI_SYSTEM_MAX; sc->userspace_nb.notifier_call = &scmi_userspace_notifier; sc->dev = &sdev->dev; + dev_set_drvdata(&sdev->dev, sc);
INIT_WORK(&sc->suspend_work, scmi_suspend_work_func);
@@ -363,6 +360,18 @@ static int scmi_syspower_probe(struct scmi_device *sdev) NULL, &sc->userspace_nb); }
+static int scmi_system_power_resume(struct device *dev) +{ + struct scmi_syspower_conf *sc = dev_get_drvdata(dev); + + sc->state = SCMI_SYSPOWER_IDLE; + return 0; +} + +static const struct dev_pm_ops scmi_system_power_pmops = { + SET_SYSTEM_SLEEP_PM_OPS(NULL, scmi_system_power_resume) +}; + static const struct scmi_device_id scmi_id_table[] = { { SCMI_PROTOCOL_SYSTEM, "syspower" }, { }, @@ -370,6 +379,9 @@ static const struct scmi_device_id scmi_id_table[] = { MODULE_DEVICE_TABLE(scmi, scmi_id_table);
static struct scmi_driver scmi_system_power_driver = { + .driver = { + .pm = &scmi_system_power_pmops, + }, .name = "scmi-system-power", .probe = scmi_syspower_probe, .id_table = scmi_id_table,