The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. The driver splits the locking function into two parts: local_irq_save() and uart_port_lock() and this breaks PREEMPT_RT. Delay handling sysrq until port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> --- drivers/tty/serial/pxa.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c index 46e70e155aab2..e395ff29c1a2c 100644 --- a/drivers/tty/serial/pxa.c +++ b/drivers/tty/serial/pxa.c @@ -151,7 +151,7 @@ static inline void receive_chars(struct uart_pxa_port *up, int *status) flag = TTY_FRAME; } - if (uart_handle_sysrq_char(&up->port, ch)) + if (uart_prepare_sysrq_char(&up->port, ch)) goto ignore_char; uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag); @@ -232,7 +232,7 @@ static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id) check_modem_status(up); if (lsr & UART_LSR_THRE) transmit_chars(up); - uart_port_unlock(&up->port); + uart_unlock_and_check_sysrq(&up->port); return IRQ_HANDLED; } @@ -604,13 +604,10 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count) int locked = 1; clk_enable(up->clk); - local_irq_save(flags); - if (up->port.sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(&up->port); + if (oops_in_progress) + locked = uart_port_trylock_irqsave(&up->port, &flags); else - uart_port_lock(&up->port); + uart_port_lock_irqsave(&up->port, &flags); /* * First save the IER then disable the interrupts @@ -628,10 +625,8 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count) serial_out(up, UART_IER, ier); if (locked) - uart_port_unlock(&up->port); - local_irq_restore(flags); + uart_port_unlock_irqrestore(&up->port, flags); clk_disable(up->clk); - } #ifdef CONFIG_CONSOLE_POLL -- 2.43.0
