The defunct low_latency input steering executed flush_to_ldisc()
directly from interrupt context so dropping the port lock was
necessary to avoid deadlock. That steering was removed by
commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25
Author: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Date: Sat Feb 22 07:31:21 2014 -0500
tty: Fix low_latency BUG
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 4868056..9ef77a5 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1489,9 +1489,8 @@ unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
break;
lsr = serial_in(up, UART_LSR);
} while (lsr & (UART_LSR_DR | UART_LSR_BI));
- spin_unlock(&port->lock);
+
tty_flip_buffer_push(&port->state->port);
- spin_lock(&port->lock);
return lsr;
}
EXPORT_SYMBOL_GPL(serial8250_rx_chars);
--
2.7.0
--
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