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Subject[PATCH 2.5] : ir255_nsc_speed-4.diff
From
ir255_nsc_speed-4.diff :
----------------------
o [FEATURE] Cleanly change speed back to 9600bps
o [CORRECT] Change speed under spinlock/irq disabled
o [CORRECT] Make sure interrupt handlers don't mess irq mask
o [CORRECT] Don't change speed if we haven't fully finished to Tx

diff -u -p linux/include/net/irda/nsc-ircc.d2.h linux/include/net/irda/nsc-ircc.h
--- linux/include/net/irda/nsc-ircc.d2.h Mon Jul 15 16:13:58 2002
+++ linux/include/net/irda/nsc-ircc.h Mon Jul 15 16:18:55 2002
@@ -253,6 +253,7 @@ struct nsc_ircc_cb {

__u32 flags; /* Interface flags */
__u32 new_speed;
+ int speed_cnt; /* Number of frames before speed change */
int index; /* Instance index */

struct pm_dev *dev;
diff -u -p linux/drivers/net/irda/nsc-ircc.d2.c linux/drivers/net/irda/nsc-ircc.c
--- linux/drivers/net/irda/nsc-ircc.d2.c Mon Jul 15 15:42:50 2002
+++ linux/drivers/net/irda/nsc-ircc.c Tue Jul 16 10:43:37 2002
@@ -953,6 +953,7 @@ static void nsc_ircc_change_dongle_speed
*
* Change the speed of the device
*
+ * This function *must* be called with irq off and spin-lock.
*/
static void nsc_ircc_change_speed(struct nsc_ircc_cb *self, __u32 speed)
{
@@ -1048,7 +1049,6 @@ static void nsc_ircc_change_speed(struct

/* Restore BSR */
outb(bank, iobase+BSR);
- netif_wake_queue(dev);

}

@@ -1074,20 +1074,30 @@ static int nsc_ircc_hard_xmit_sir(struct

netif_stop_queue(dev);

+ /* Make sure tests *& speed change are atomic */
+ spin_lock_irqsave(&self->lock, flags);
+
/* Check if we need to change the speed */
speed = irda_get_next_speed(skb);
if ((speed != self->io.speed) && (speed != -1)) {
- /* Check for empty frame */
+ /* Check for empty frame. */
if (!skb->len) {
- nsc_ircc_change_speed(self, speed);
+ /* If we just sent a frame, we get called before
+ * the last bytes get out (because of the SIR FIFO).
+ * If this is the case, let interrupt handler change
+ * the speed itself... Jean II */
+ if (self->io.direction == IO_RECV)
+ nsc_ircc_change_speed(self, speed);
+ else
+ self->new_speed = speed;
+ spin_unlock_irqrestore(&self->lock, flags);
dev_kfree_skb(skb);
+ netif_wake_queue(dev);
return 0;
} else
self->new_speed = speed;
}

- spin_lock_irqsave(&self->lock, flags);
-
/* Save current bank */
bank = inb(iobase+BSR);

@@ -1126,20 +1136,34 @@ static int nsc_ircc_hard_xmit_fir(struct

netif_stop_queue(dev);

+ /* Make sure tests *& speed change are atomic */
+ spin_lock_irqsave(&self->lock, flags);
+
/* Check if we need to change the speed */
speed = irda_get_next_speed(skb);
if ((speed != self->io.speed) && (speed != -1)) {
- /* Check for empty frame */
+ /* Check for empty frame. */
if (!skb->len) {
- nsc_ircc_change_speed(self, speed);
+ /* If we are currently transmitting, defer to
+ * interrupt handler. - Jean II */
+ if(self->tx_fifo.len == 0)
+ nsc_ircc_change_speed(self, speed);
+ else {
+ self->new_speed = speed;
+ self->speed_cnt = self->tx_fifo.len;
+ }
+ spin_unlock_irqrestore(&self->lock, flags);
dev_kfree_skb(skb);
+ netif_wake_queue(dev);
return 0;
- } else
+ } else {
self->new_speed = speed;
+ /* Save the number of frames currently in the fifo
+ * so that we know *when* to change the speed. */
+ self->speed_cnt = self->tx_fifo.len + 1;
+ }
}

- spin_lock_irqsave(&self->lock, flags);
-
/* Save current bank */
bank = inb(iobase+BSR);

@@ -1334,16 +1358,23 @@ static int nsc_ircc_dma_xmit_complete(st
self->stats.tx_packets++;
}

- /* Check if we need to change the speed */
- if (self->new_speed) {
- nsc_ircc_change_speed(self, self->new_speed);
- self->new_speed = 0;
- }
-
/* Finished with this frame, so prepare for next */
self->tx_fifo.ptr++;
self->tx_fifo.len--;

+ /* Check if we need to change the speed.
+ * Do it after self->tx_fifo.len--; to avoid races with
+ * nsc_ircc_hard_xmit_fir().
+ * We do it synchronous to the packets in the fifo, so that's
+ * why we wait for the right frame to do it. - Jean II */
+ if ((self->new_speed) && (--self->speed_cnt == 0)) {
+ /* There seem to be some issue with corrupting the
+ * frame just before a speed change. Workaround. Jean II */
+ udelay(100);
+ nsc_ircc_change_speed(self, self->new_speed);
+ self->new_speed = 0;
+ }
+
/* Any frames to be sent back-to-back? */
if (self->tx_fifo.len) {
nsc_ircc_dma_xmit(self, iobase);
@@ -1634,7 +1665,12 @@ static void nsc_ircc_sir_interrupt(struc
}
/* Check if transmission has completed */
if (eir & EIR_TXEMP_EV) {
- /* Check if we need to change the speed? */
+ /* Turn around and get ready to receive some data */
+ self->io.direction = IO_RECV;
+ self->ier = IER_RXHDL_IE;
+ /* Check if we need to change the speed?
+ * Need to be after self->io.direction to avoid race with
+ * nsc_ircc_hard_xmit_sir() - Jean II */
if (self->new_speed) {
IRDA_DEBUG(2, __FUNCTION__ "(), Changing speed!\n");
nsc_ircc_change_speed(self, self->new_speed);
@@ -1649,9 +1685,6 @@ static void nsc_ircc_sir_interrupt(struc
return;
}
}
- /* Turn around and get ready to receive some data */
- self->io.direction = IO_RECV;
- self->ier = IER_RXHDL_IE;
}

/* Rx FIFO threshold or timeout */
-
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