On Mon, 4 Apr 2005 11:11:01 -0700
Eric Brower <[EMAIL PROTECTED]> wrote:
> In tty_ioctl.c tty_wait_until_sent() if the timeout variable is set to
> zero (which many callers do explicitly) it gets reassigned to
> MAX_SCHEDULE_TIMEOUT (this is LONG_MAX). If there are no characters
> waiting to be sent (!tty->driver->chars_in_buffer(tty)) we drop out of
> our loop and supply the timeout variable to uart_wait_until_sent
> (tty->driver->wait_until_sent). The problem is uart_wait_until_sent
> is specified with a timeout argument of type int, not long. This
> becomes -1 in uart_wait_until_sent, which I don't think is intended.
> If your port->timeout value in this function is also zero (as seems
> the case with sunsab), this seems doubly bad and leads to massive
> mdelay times in uart_wait_until_sent. This will appear to you as a
> hung getty.
Good catch. That third argument should be "unsigned long timeout"
indeed. I've pointed this out in private email to Russell, Linus
and Andrew.
uart_update_timeout() calls done by the driver (in this case sunsab.c)
should be updating the port->timeout value properly. Indeed, sunsab.c
fails to call uart_update_timeout() at all.
Hmmm, I wonder if the port->uartclk we use in sunsab.c needs to be
multiplied by 16, like sunsu.c does.
Anyways, this patch below should be a step in the right direction.
===== drivers/serial/sunsab.c 1.38 vs edited =====
--- 1.38/drivers/serial/sunsab.c 2004-12-08 21:31:16 -08:00
+++ edited/drivers/serial/sunsab.c 2005-04-04 12:17:25 -07:00
@@ -682,7 +682,8 @@
/* Internal routine, port->lock is held and local interrupts are disabled. */
static void sunsab_convert_to_sab(struct uart_sunsab_port *up, unsigned int
cflag,
- unsigned int iflag, int baud)
+ unsigned int iflag, unsigned int baud,
+ unsigned int quot)
{
unsigned int ebrg;
unsigned char dafo;
@@ -766,6 +767,9 @@
up->port.ignore_status_mask |= (SAB82532_ISR0_RPF |
SAB82532_ISR0_TCD);
+ uart_update_timeout(&up->port, cflag,
+ (up->port.uartclk / (16 * quot)));
+
/* Now bang the new settings into the chip. */
sunsab_cec_wait(up);
sunsab_tec_wait(up);
@@ -784,10 +788,11 @@
{
struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
unsigned long flags;
- int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
+ unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
+ unsigned int quot = uart_get_divisor(port, baud);
spin_lock_irqsave(&up->port.lock, flags);
- sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud);
+ sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud,
quot);
spin_unlock_irqrestore(&up->port.lock, flags);
}
@@ -880,7 +885,7 @@
{
struct uart_sunsab_port *up = &sunsab_ports[con->index];
unsigned long flags;
- int baud;
+ unsigned int baud, quot;
printk("Console: ttyS%d (SAB82532)\n",
(sunsab_reg.minor - 64) + con->index);
@@ -926,7 +931,8 @@
SAB82532_IMR1_XPR;
writeb(up->interrupt_mask1, &up->regs->w.imr1);
- sunsab_convert_to_sab(up, con->cflag, 0, baud);
+ quot = uart_get_divisor(&up->port, baud);
+ sunsab_convert_to_sab(up, con->cflag, 0, baud, quot);
sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
spin_unlock_irqrestore(&up->port.lock, flags);
-
To unsubscribe from this list: send the line "unsubscribe ultralinux" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
