Commit ca79b7b4 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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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: default avatarJoris van Rantwijk <jorispubl@xs4all.nl>
Signed-off-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 3f141e2a
......@@ -326,10 +326,16 @@ static void acm_rx_tasklet(unsigned long _acm)
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 @@ next_buffer:
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 @@ static int acm_tty_open(struct tty_struct *tty, struct file *filp)
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 @@ static int acm_tty_open(struct tty_struct *tty, struct file *filp)
list_add(&(acm->rb[i].list), &acm->spare_read_bufs);
}
acm->throttle = 0;
tasklet_schedule(&acm->urb_task);
done:
......
......@@ -73,6 +73,13 @@ struct usb_cdc_acm_descriptor {
__u8 bmCapabilities;
} __attribute__ ((packed));
/* capabilities from 5.2.3.3 */
#define USB_CDC_COMM_FEATURE 0x01
#define USB_CDC_CAP_LINE 0x02
#define USB_CDC_CAP_BRK 0x04
#define USB_CDC_CAP_NOTIFY 0x08
/* "Union Functional Descriptor" from CDC spec 5.2.3.8 */
struct usb_cdc_union_desc {
__u8 bLength;
......
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