From d0cd9c8d0fd59bc7d140f3d60cf02e1d80376dab Mon Sep 17 00:00:00 2001 From: Praveen Talari Date: Thu, 2 Jul 2026 17:11:50 +0530 Subject: serial: qcom-geni: add force suspend/resume to system sleep callbacks During system sleep the hardware resources (clocks, interconnect) are not gated because the runtime-suspend callback is never invoked from the system sleep path. This prevents the platform from reaching its lowest idle state. The system sleep callbacks qcom_geni_serial_suspend() and qcom_geni_serial_resume() rely solely on uart_suspend_port() / uart_resume_port() to manage power. uart_suspend_port() drives the UART PM state machine to UART_PM_STATE_OFF, which in turn calls pm_runtime_put_sync() and eventually the runtime-suspend callback. However, if the runtime-PM usage count is still elevated at the time of system sleep (e.g. the port is held active by an open file descriptor), the runtime-suspend callback is never invoked and the hardware resources (clocks, interconnect) remain enabled across suspend, preventing the platform from reaching its lowest idle state. Fix this by calling pm_runtime_force_suspend() at the end of qcom_geni_serial_suspend() so that the runtime-suspend callback is always executed regardless of the usage count, and by calling pm_runtime_force_resume() at the start of qcom_geni_serial_resume() to restore those resources before uart_resume_port() re-opens the port. Signed-off-by: Praveen Talari Link: https://patch.msgid.link/20260702-add_force_suspend_resume_to_system_sleep_callbacks-v2-1-b79e254a7015@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 3e460b0358eb..949e16ead7b5 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1985,6 +1985,7 @@ static int qcom_geni_serial_suspend(struct device *dev) struct qcom_geni_serial_port *port = dev_get_drvdata(dev); struct uart_port *uport = &port->uport; struct qcom_geni_private_data *private_data = uport->private_data; + int ret; /* * This is done so we can hit the lowest possible state in suspend @@ -1994,7 +1995,19 @@ static int qcom_geni_serial_suspend(struct device *dev) geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ACTIVE_ONLY); geni_icc_set_bw(&port->se); } - return uart_suspend_port(private_data->drv, uport); + + ret = uart_suspend_port(private_data->drv, uport); + if (ret) + return ret; + + /* + * When no_console_suspend is set the console must remain active + * across system sleep, so skip the force suspend path. + */ + if (!console_suspend_enabled && uart_console(uport)) + return 0; + + return pm_runtime_force_suspend(dev); } static int qcom_geni_serial_resume(struct device *dev) @@ -2004,6 +2017,10 @@ static int qcom_geni_serial_resume(struct device *dev) struct uart_port *uport = &port->uport; struct qcom_geni_private_data *private_data = uport->private_data; + ret = pm_runtime_force_resume(dev); + if (ret) + return ret; + ret = uart_resume_port(private_data->drv, uport); if (uart_console(uport)) { geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS); -- cgit v1.2.3