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Commit 2918eca4 authored by Ulrich Hecht's avatar Ulrich Hecht Committed by Greg Kroah-Hartman
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serial: sh-sci: fix break handling for sysrq 



[ 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: default avatarUlrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20210816162201.28801-1-uli+renesas@fpond.eu


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent d02a1c5f

drivers/tty/serial/sh-sci.c

+6 −1
Original line number Diff line number Diff line
@@ -1763,6 +1763,10 @@ 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;
@@ -1842,7 +1846,8 @@ 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 */