Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ca79b7b4 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
Browse files

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

drivers/usb/class/cdc-acm.c

+18 −11
Original line number Diff line number Diff line
@@ -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 @@ static void acm_rx_tasklet(unsigned long _acm) 
	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:

include/linux/usb/cdc.h

+7 −0
Original line number Diff line number Diff line
@@ -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;