[PATCH] serial: qcom-geni: power the console back up on system resume

[David Heidelberg via B4 Relay]

From: David Heidelberg <david@xxxxxxx>

The console holds a runtime PM reference on its port, which keeps the
port powered while the tty is closed. On system suspend
pm_runtime_force_suspend() powers the port down regardless, but a single
reference makes pm_runtime_need_not_resume() report the port as not in
use, so it is marked runtime suspended instead of being flagged for
pm_runtime_force_resume(). On system resume the port therefore stays
powered down while uart_resume_port() goes on to program the termios
settings and re-enable the console.

If the tty has been opened before, uart_resume_port() ends up in
startup(), whose runtime PM reference powers the port up again, and only
the register writes made before that are lost. If the tty has never been
opened (no getty on the port, /dev/console backed by another console),
nothing powers the port back up and the console stays dead after the
first suspend.

Resume the port explicitly before uart_resume_port() when the console
was force suspended.

Assisted-by: LLM
Fixes: aee1f94dab13 ("serial: qcom-geni: remove .pm callback, use runtime PM in startup/shutdown")
Signed-off-by: David Heidelberg <david@xxxxxxx>
---
 drivers/tty/serial/qcom_geni_serial.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index a180a00c9e23d..0c9164a1fccda 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -2100,16 +2100,22 @@ static int qcom_geni_serial_resume(struct device *dev)
 	struct qcom_geni_private_data *private_data = uport->private_data;
 
 	if (console_suspend_enabled || !uart_console(uport)) {
 		ret = pm_runtime_force_resume(dev);
 		if (ret)
 			return ret;
 	}
 
+	if (console_suspend_enabled && uart_console(uport)) {
+		ret = pm_runtime_resume(dev);
+		if (ret < 0)
+			return ret;
+	}
+
 	ret = uart_resume_port(private_data->drv, uport);
 	if (uart_console(uport)) {
 		geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
 		geni_icc_set_bw(&port->se);
 	}
 	return ret;
 }
 

---
base-commit: 3d83758432b5e6ed9507500a57efb0f3af41ee7d
change-id: 20260918-qcom-geni-pm-e0ff5899c948
prerequisite-change-id: 20260828-serial-qcom-geni-fix-unbalanced-rpm-resume-814e630326b9:v1
prerequisite-patch-id: a2666a59a68190a3f438cec8aa167111c21dc8ca

Best regards,
--  
David Heidelberg <david@xxxxxxx>