ChangeSet 1.791, 2002/12/05 14:21:38-08:00, [EMAIL PROTECTED]

[PATCH] tiglusb timeouts

It addresses the timeout parameter in the tiglusb driver.

1.  timeout could be 0, causing a divide-by-zero.
The patch prevents this.

2.  The timeout value to usb_bulk_msg() could be rounded
down to cause a divide-by-zero if timeout was < 10, e.g. 9,
in:
        result = usb_bulk_msg (s->dev, pipe, buffer, bytes_to_read,
                               &bytes_read, HZ / (timeout / 10));
9 / 10 == 0 => divide-by-zero !!

3.  The timeout value above doesn't do very well on converting
timeout to tenths of seconds.  Even for the default timeout
value of 15 (1.5 seconds), it becomes:
        HZ / (15 / 10) == HZ / 1 == HZ, or 1 second.
The patch corrects this formula to use:
        (HZ * 10) / timeout


diff -Nru a/drivers/usb/tiglusb.c b/drivers/usb/tiglusb.c
--- a/drivers/usb/tiglusb.c     Thu Dec  5 14:48:26 2002
+++ b/drivers/usb/tiglusb.c     Thu Dec  5 14:48:26 2002
@@ -185,7 +185,7 @@
 
        pipe = usb_rcvbulkpipe (s->dev, 1);
        result = usb_bulk_msg (s->dev, pipe, buffer, bytes_to_read,
-                              &bytes_read, HZ / (timeout / 10));
+                              &bytes_read, HZ * 10 / timeout);
        if (result == -ETIMEDOUT) {     /* NAK */
                ret = result;
                if (!bytes_read) {
@@ -242,7 +242,7 @@
 
        pipe = usb_sndbulkpipe (s->dev, 2);
        result = usb_bulk_msg (s->dev, pipe, buffer, bytes_to_write,
-                              &bytes_written, HZ / (timeout / 10));
+                              &bytes_written, HZ * 10 / timeout);
 
        if (result == -ETIMEDOUT) {     /* NAK */
                warn ("tiglusb_write, NAK received.");
@@ -446,6 +446,8 @@
        if (ints[0] > 0) {
                timeout = ints[1];
        }
+       if (!timeout)
+               timeout = TIMAXTIME;
 
        return 1;
 }
@@ -487,6 +489,9 @@
 
        info (DRIVER_DESC ", " DRIVER_VERSION);
 
+       if (!timeout)
+               timeout = TIMAXTIME;
+
        return 0;
 }
 
@@ -509,6 +514,6 @@
 MODULE_LICENSE (DRIVER_LICENSE);
 
 MODULE_PARM (timeout, "i");
-MODULE_PARM_DESC (timeout, "Timeout (default=1.5 seconds)");
+MODULE_PARM_DESC (timeout, "Timeout in tenths of seconds (default=1.5 seconds)");
 
 /* --------------------------------------------------------------------- */


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