From: Ulrich Hecht <uli+renesas@xxxxxxxx> [ Upstream commit 87b8061bad9bd4b549b2daf36ffbaa57be2789a2 ] This fixes two issues that cause the sysrq sequence to be inadvertently aborted on SCIF serial consoles: - a NUL character remains in the RX queue after a break has been detected, which is then passed on to uart_handle_sysrq_char() - the break interrupt is handled twice on controllers with multiplexed ERI and BRI interrupts Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx> Link: https://lore.kernel.org/r/20210816162201.28801-1-uli+renesas@xxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/serial/sh-sci.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 70898a999a49..f700bfaef129 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1760,6 +1760,10 @@ static irqreturn_t sci_br_interrupt(int irq, void *ptr) /* Handle BREAKs */ sci_handle_breaks(port); + + /* drop invalid character received before break was detected */ + serial_port_in(port, SCxRDR); + sci_clear_SCxSR(port, SCxSR_BREAK_CLEAR(port)); return IRQ_HANDLED; @@ -1839,7 +1843,8 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr) ret = sci_er_interrupt(irq, ptr); /* Break Interrupt */ - if ((ssr_status & SCxSR_BRK(port)) && err_enabled) + if (s->irqs[SCIx_ERI_IRQ] != s->irqs[SCIx_BRI_IRQ] && + (ssr_status & SCxSR_BRK(port)) && err_enabled) ret = sci_br_interrupt(irq, ptr); /* Overrun Interrupt */ -- 2.30.2
