USB: cdc-acm: fix incorrect throtteling, make set_control optional
this is Joris' fixes reshuffelled and features renamed as David requested.
- acm_set_control is not mandatory, honour that
- throtteling is reset upon open
- throtteling is read consistently when processing input data
Signed-off-by: Joris van Rantwijk <jorispubl@xs4all.nl>
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 9819962..023cf5d 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -326,10 +326,16 @@
struct tty_struct *tty = acm->tty;
struct acm_ru *rcv;
unsigned long flags;
- int i = 0;
+ unsigned char throttled;
dbg("Entering acm_rx_tasklet");
- if (!ACM_READY(acm) || acm->throttle)
+ if (!ACM_READY(acm))
+ return;
+
+ spin_lock(&acm->throttle_lock);
+ throttled = acm->throttle;
+ spin_unlock(&acm->throttle_lock);
+ if (throttled)
return;
next_buffer:
@@ -346,22 +352,20 @@
dbg("acm_rx_tasklet: procesing buf 0x%p, size = %d", buf, buf->size);
tty_buffer_request_room(tty, buf->size);
- if (!acm->throttle)
+ spin_lock(&acm->throttle_lock);
+ throttled = acm->throttle;
+ spin_unlock(&acm->throttle_lock);
+ if (!throttled)
tty_insert_flip_string(tty, buf->base, buf->size);
tty_flip_buffer_push(tty);
- spin_lock(&acm->throttle_lock);
- if (acm->throttle) {
- dbg("Throtteling noticed");
- memmove(buf->base, buf->base + i, buf->size - i);
- buf->size -= i;
- spin_unlock(&acm->throttle_lock);
+ if (throttled) {
+ dbg("Throttling noticed");
spin_lock_irqsave(&acm->read_lock, flags);
list_add(&buf->list, &acm->filled_read_bufs);
spin_unlock_irqrestore(&acm->read_lock, flags);
return;
}
- spin_unlock(&acm->throttle_lock);
spin_lock_irqsave(&acm->read_lock, flags);
list_add(&buf->list, &acm->spare_read_bufs);
@@ -467,7 +471,8 @@
goto bail_out;
}
- if (0 > acm_set_control(acm, acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS))
+ if (0 > acm_set_control(acm, acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS) &&
+ (acm->ctrl_caps & USB_CDC_CAP_LINE))
goto full_bailout;
INIT_LIST_HEAD(&acm->spare_read_urbs);
@@ -480,6 +485,8 @@
list_add(&(acm->rb[i].list), &acm->spare_read_bufs);
}
+ acm->throttle = 0;
+
tasklet_schedule(&acm->urb_task);
done: