[PATCH 3/14] hvc_console: Dont always kick the poll thread in interrupt

[Anton Blanchard]

From: Milton Miller <miltonm at bga.com>

Have the hvc console code try to pull characters immediately when
receiving an interrupt, and kick the poll thread only if the
immediate poll indicates it needed a call back to do more work.

Signed-off-by: Milton Miller <miltonm at bga.com>
Signed-off-by: Anton Blanchard <anton at samba.org>

diff -puN drivers/char/hvc_console.c~hvc-console-irq-nodelay drivers/char/hvc_console.c
--- gr_work_udbg/drivers/char/hvc_console.c~hvc-console-irq-nodelay	2005-02-08 00:42:40.386023479 -0600
+++ gr_work_udbg-miltonm/drivers/char/hvc_console.c	2005-02-08 00:42:40.396021893 -0600
@@ -254,13 +254,17 @@ static void hvc_kick(void)
 	wake_up_process(hvc_task);
 }
 
+static int hvc_poll(struct hvc_struct *hp);
+
 /*
  * NOTE: This API isn't used if the console adapter doesn't support interrupts.
  * In this case the console is poll driven.
  */
 static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
 {
-	hvc_kick();
+	/* if hvc_poll request a repoll, then kick the hvcd thread */
+	if (hvc_poll(dev_instance))
+		hvc_kick();
 	return IRQ_HANDLED;
 }
 
@@ -598,8 +602,8 @@ static int hvc_poll(struct hvc_struct *h
 
 		/*
 		 * Account for the total amount read in one loop, and if above
-		 * 64 bytes, we do a quick schedule loop to let the tty grok the
-		 * data and eventually throttle us.
+		 * 64 bytes, we do a quick schedule loop to let the tty grok
+		 * the data and eventually throttle us.
 		 */
 		read_total += n;
 		if (read_total >= 64) {
_