From ed8485fb340056c4d9062e9d2697c8402dd19eb0 Mon Sep 17 00:00:00 2001
From: Paul Fulghum <paulkf@microgate.com>
Date: Wed, 6 Feb 2008 01:37:18 -0800
Subject: [PATCH] synclink_gt fix missed serial input signal changes

Fix missed serial input signal changes caused by rereading the serial
status register during interrupt processing.  Now processing is performed
on original status register value.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/char/synclink_gt.c | 68 +++++++++++++++++++++-----------------
 1 file changed, 37 insertions(+), 31 deletions(-)

diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 5f6a5da696c..1f954acf2ba 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -2039,37 +2039,41 @@ static void bh_transmit(struct slgt_info *info)
 		tty_wakeup(tty);
 }
 
-static void dsr_change(struct slgt_info *info)
+static void dsr_change(struct slgt_info *info, unsigned short status)
 {
-	get_signals(info);
+	if (status & BIT3) {
+		info->signals |= SerialSignal_DSR;
+		info->input_signal_events.dsr_up++;
+	} else {
+		info->signals &= ~SerialSignal_DSR;
+		info->input_signal_events.dsr_down++;
+	}
 	DBGISR(("dsr_change %s signals=%04X\n", info->device_name, info->signals));
 	if ((info->dsr_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
 		slgt_irq_off(info, IRQ_DSR);
 		return;
 	}
 	info->icount.dsr++;
-	if (info->signals & SerialSignal_DSR)
-		info->input_signal_events.dsr_up++;
-	else
-		info->input_signal_events.dsr_down++;
 	wake_up_interruptible(&info->status_event_wait_q);
 	wake_up_interruptible(&info->event_wait_q);
 	info->pending_bh |= BH_STATUS;
 }
 
-static void cts_change(struct slgt_info *info)
+static void cts_change(struct slgt_info *info, unsigned short status)
 {
-	get_signals(info);
+	if (status & BIT2) {
+		info->signals |= SerialSignal_CTS;
+		info->input_signal_events.cts_up++;
+	} else {
+		info->signals &= ~SerialSignal_CTS;
+		info->input_signal_events.cts_down++;
+	}
 	DBGISR(("cts_change %s signals=%04X\n", info->device_name, info->signals));
 	if ((info->cts_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
 		slgt_irq_off(info, IRQ_CTS);
 		return;
 	}
 	info->icount.cts++;
-	if (info->signals & SerialSignal_CTS)
-		info->input_signal_events.cts_up++;
-	else
-		info->input_signal_events.cts_down++;
 	wake_up_interruptible(&info->status_event_wait_q);
 	wake_up_interruptible(&info->event_wait_q);
 	info->pending_bh |= BH_STATUS;
@@ -2090,20 +2094,21 @@ static void cts_change(struct slgt_info *info)
 	}
 }
 
-static void dcd_change(struct slgt_info *info)
+static void dcd_change(struct slgt_info *info, unsigned short status)
 {
-	get_signals(info);
+	if (status & BIT1) {
+		info->signals |= SerialSignal_DCD;
+		info->input_signal_events.dcd_up++;
+	} else {
+		info->signals &= ~SerialSignal_DCD;
+		info->input_signal_events.dcd_down++;
+	}
 	DBGISR(("dcd_change %s signals=%04X\n", info->device_name, info->signals));
 	if ((info->dcd_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
 		slgt_irq_off(info, IRQ_DCD);
 		return;
 	}
 	info->icount.dcd++;
-	if (info->signals & SerialSignal_DCD) {
-		info->input_signal_events.dcd_up++;
-	} else {
-		info->input_signal_events.dcd_down++;
-	}
 #if SYNCLINK_GENERIC_HDLC
 	if (info->netcount) {
 		if (info->signals & SerialSignal_DCD)
@@ -2126,20 +2131,21 @@ static void dcd_change(struct slgt_info *info)
 	}
 }
 
-static void ri_change(struct slgt_info *info)
+static void ri_change(struct slgt_info *info, unsigned short status)
 {
-	get_signals(info);
+	if (status & BIT0) {
+		info->signals |= SerialSignal_RI;
+		info->input_signal_events.ri_up++;
+	} else {
+		info->signals &= ~SerialSignal_RI;
+		info->input_signal_events.ri_down++;
+	}
 	DBGISR(("ri_change %s signals=%04X\n", info->device_name, info->signals));
 	if ((info->ri_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
 		slgt_irq_off(info, IRQ_RI);
 		return;
 	}
-	info->icount.dcd++;
-	if (info->signals & SerialSignal_RI) {
-		info->input_signal_events.ri_up++;
-	} else {
-		info->input_signal_events.ri_down++;
-	}
+	info->icount.rng++;
 	wake_up_interruptible(&info->status_event_wait_q);
 	wake_up_interruptible(&info->event_wait_q);
 	info->pending_bh |= BH_STATUS;
@@ -2190,13 +2196,13 @@ static void isr_serial(struct slgt_info *info)
 	}
 
 	if (status & IRQ_DSR)
-		dsr_change(info);
+		dsr_change(info, status);
 	if (status & IRQ_CTS)
-		cts_change(info);
+		cts_change(info, status);
 	if (status & IRQ_DCD)
-		dcd_change(info);
+		dcd_change(info, status);
 	if (status & IRQ_RI)
-		ri_change(info);
+		ri_change(info, status);
 }
 
 static void isr_rdma(struct slgt_info *info)
-- 
2.41.0