Re: Serial Driver Bug?? (and patch!)

Andrew E. Mileski (aem@nic.ott.hookup.net)
Sun, 28 Apr 1996 18:26:28 -0400 (EDT)

> > Do any of these problems (cat /proc/ioports causing system crashes,
> > etc.) happen *before* the first time the serial driver is loaded?
>
> No. In fact, they only happen after ther serial driver has been loaded
> and then unloaded (and possibly loaded again). The problem seems to be
> that 'release_region' is never called at module unload time, and so the
> kernel's resource tables contain wild pointers.
>
> Below is a patch that I send to Andrew yesterday; it fixes the problem
> for me. It also adds a KERN_INFO priority to some of the printk()s
> (so my console doesn't get littered by them when kerneld loads the
> module). Comments welcome.

The patch works fine for me too. Thanks! :-)

Too bad you can't fix the AIC7XXX driver so I can actually use a
v1.3.9* kernel for more than 3 minutes...

I go through /proc/ioports more often than most because my PnP
code deals with hardware resources. In fact, I re-wrote the
I/O and DMA code to unify it. This unified code also gets me
a /proc/addresses and /proc/irq (not the same as /proc/interrupts).
Hopefully PnP will make it into a v1.5.* (or is that v2.1.* ?)
kernel.

Anyhoot, thanks.

--
Andrew E. Mileski
mailto:aem@ott.hookup.net   http://www.redhat.com/~aem/
Linux Plug-and-Play Project http://www.redhat.com/pnp/
"You can't have everything. Where would you put it?" - Steven Wright


Index: linux/drivers/char/serial.c
===================================================================
RCS file: /usr/local/cvsroot/linux/drivers/char/serial.c,v
retrieving revision 1.1.1.4
diff -u -r1.1.1.4 serial.c
--- serial.c	1996/04/18 20:36:08	1.1.1.4
+++ serial.c	1996/04/27 09:27:41
@@ -2448,7 +2448,7 @@
  */
 static void show_serial_version(void)
 {
- 	printk("%s version %s with", serial_name, serial_version);
+ 	printk(KERN_INFO "%s version %s with", serial_name, serial_version);
 #ifdef CONFIG_HUB6
 	printk(" HUB-6");
 #define SERIAL_OPT
@@ -2797,7 +2797,7 @@
 		autoconfig(info);
 		if (info->type == PORT_UNKNOWN)
 			continue;
-		printk("tty%02d%s at 0x%04x (irq = %d)", info->line, 
+		printk(KERN_INFO "tty%02d%s at 0x%04x (irq = %d)", info->line, 
 		       (info->flags & ASYNC_FOURPORT) ? " FourPort" : "",
 		       info->port, info->irq);
 		switch (info->type) {
@@ -2867,7 +2867,7 @@
 		printk("register_serial(): autoconfig failed\n");
 		return -1;
 	}
-	printk("tty%02d at 0x%04x (irq = %d)", info->line, 
+	printk(KERN_INFO "tty%02d at 0x%04x (irq = %d)", info->line, 
 	       info->port, info->irq);
 	switch (info->type) {
 	case PORT_8250:
@@ -2895,7 +2895,7 @@
 	if (info->tty)
 		tty_hangup(info->tty);
 	info->type = PORT_UNKNOWN;
-	printk("tty%02d unloaded\n", info->line);
+	printk(KERN_INFO "tty%02d unloaded\n", info->line);
 	restore_flags(flags);
 }
 
@@ -2909,6 +2909,7 @@
 {
 	unsigned long flags;
 	int e1, e2;
+	int i;
 
 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
 	save_flags(flags);
@@ -2923,5 +2924,10 @@
 		printk("SERIAL: failed to unregister callout driver (%d)\n", 
 		       e2);
 	restore_flags(flags);
+
+	for (i = 0; i < NR_PORTS; i++) {
+		if (rs_table[i].type != PORT_UNKNOWN)
+			release_region(rs_table[i].port, 8);
+	}
 }
 #endif /* MODULE */