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serial: 8250_omap: Remove auto-IXON flow control

Message ID 1435411735-4053-1-git-send-email-peter@hurleysoftware.com (mailing list archive)
State New, archived
Headers show

Commit Message

Peter Hurley June 27, 2015, 1:28 p.m. UTC 
OMAP h/w-assisted IXON flow control is borked. The transmitter becomes
stuck if XON is never received; clearing the fifos or resetting the
rx flow control bits has no effect.

Remove auto-IXANY as well, since without auto-IXON, it has no purpose.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
 drivers/tty/serial/8250/8250_omap.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)
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Patch

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 9782043..7e58750 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -427,12 +427,9 @@  static void omap_8250_set_termios(struct uart_port *port,
 		priv->efr |= UART_EFR_CTS;
 	} else	if (up->port.flags & UPF_SOFT_FLOW) {
 		/*
-		 * IXON Flag:
-		 * Enable XON/XOFF flow control on input.
-		 * Receiver compares XON1, XOFF1.
+		 * OMAP rx s/w flow control is borked; the transmitter remains
+		 * stuck off even if rx flow control is subsequently disabled
 		 */
-		if (termios->c_iflag & IXON)
-			priv->efr |= OMAP_UART_SW_RX;
 
 		/*
 		 * IXOFF Flag:
@@ -443,15 +440,6 @@  static void omap_8250_set_termios(struct uart_port *port,
 			up->port.status |= UPSTAT_AUTOXOFF;
 			priv->efr |= OMAP_UART_SW_TX;
 		}
-
-		/*
-		 * IXANY Flag:
-		 * Enable any character to restart output.
-		 * Operation resumes after receiving any
-		 * character after recognition of the XOFF character
-		 */
-		if (termios->c_iflag & IXANY)
-			up->mcr |= UART_MCR_XONANY;
 	}
 	omap8250_restore_regs(up);