[PATCH][2.6.10-rc2-bk9] Assume struct uart_state closing times are in centiseconds

[Ian Abbott <abbotti@mev.co.uk>]

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Hi,

The current use of close_delay and closing_wait within serial_core.c is 
a little messed up for the following reasons:

* The values are scaled by uart_set_info() but not scaled back by 
uart_get_info(), so the values are different unless HZ==100.

* The closing_wait value is scaled by uart_set_info() and compared to an 
unscaled magic value USF_CLOSING_WAIT_NONE in uart_close().

As uart_set_info already assumes that the new values are in centisecond 
units and scaling could mess up the comparison with magic values (even 
if the magic values are scaled), I propose to store the raw centisecond 
values in struct uart_state and scale them at the point of use.  Here is 
a patch to do that.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

[-- Attachment #2: serial_closing_time.patch --]
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diff -urN linux-2.6.10-rc2-bk9/drivers/serial/serial_core.c linux-2.6.10-rc2-bk9-ia/drivers/serial/serial_core.c
--- linux-2.6.10-rc2-bk9/drivers/serial/serial_core.c	2004-11-26 17:26:07.750667256 +0000
+++ linux-2.6.10-rc2-bk9-ia/drivers/serial/serial_core.c	2004-11-26 17:46:32.523473488 +0000
@@ -751,8 +751,8 @@
 	port->flags            = (port->flags & ~UPF_CHANGE_MASK) |
 				 (new_serial.flags & UPF_CHANGE_MASK);
 	port->custom_divisor   = new_serial.custom_divisor;
-	state->close_delay     = new_serial.close_delay * HZ / 100;
-	state->closing_wait    = new_serial.closing_wait * HZ / 100;
+	state->close_delay     = new_serial.close_delay;
+	state->closing_wait    = new_serial.closing_wait;
 	port->fifosize         = new_serial.xmit_fifo_size;
 	if (state->info->tty)
 		state->info->tty->low_latency =
@@ -1191,7 +1191,7 @@
 	tty->closing = 1;
 
 	if (state->closing_wait != USF_CLOSING_WAIT_NONE)
-		tty_wait_until_sent(tty, state->closing_wait);
+		tty_wait_until_sent(tty, state->closing_wait * HZ / 100);
 
 	/*
 	 * At this point, we stop accepting input.  To do this, we
@@ -1220,7 +1220,7 @@
 
 	if (state->info->blocked_open) {
 		if (state->close_delay) {
-			msleep_interruptible(jiffies_to_msecs(state->close_delay));
+			msleep_interruptible(10 * state->close_delay);
 		}
 	} else if (!uart_console(port)) {
 		uart_change_pm(state, 3);
@@ -2082,8 +2082,8 @@
 	for (i = 0; i < drv->nr; i++) {
 		struct uart_state *state = drv->state + i;
 
-		state->close_delay     = 5 * HZ / 10;
-		state->closing_wait    = 30 * HZ;
+		state->close_delay     = 50;	/* .5 seconds */
+		state->closing_wait    = 3000;	/* 30 seconds */
 
 		init_MUTEX(&state->sem);
 	}
diff -urN linux-2.6.10-rc2-bk9/include/linux/serial_core.h linux-2.6.10-rc2-bk9-ia/include/linux/serial_core.h
--- linux-2.6.10-rc2-bk9/include/linux/serial_core.h	2004-11-26 17:26:14.787597480 +0000
+++ linux-2.6.10-rc2-bk9-ia/include/linux/serial_core.h	2004-11-26 17:49:09.499609488 +0000
@@ -241,8 +241,8 @@
  * within.
  */
 struct uart_state {
-	unsigned int		close_delay;
-	unsigned int		closing_wait;
+	unsigned int		close_delay;	/* units: centiseconds */
+	unsigned int		closing_wait;	/* units: centiseconds */
 
 #define USF_CLOSING_WAIT_INF	(0)
 #define USF_CLOSING_WAIT_NONE	(65535)