Some MBIM devices send back-to-back USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications
when sending a message over multiple fragments or when there are unsolicited
messages available.
Count up the number of USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications received
and decrement the count and submit the urb for the next response each time userspace
completes a read the response.
Signed-off-by: Greg Suarez <gsuarez@xxxxxxxxxxxxxx>
---
drivers/usb/class/cdc-wdm.c | 38 ++++++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index d3318a0..589ea58 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -101,6 +101,7 @@ struct wdm_device {
struct work_struct rxwork;
int werr;
int rerr;
+ int resp_count;
struct list_head device_list;
int (*manage_power)(struct usb_interface *, int);
@@ -262,9 +263,9 @@ static void wdm_int_callback(struct urb *urb)
}
spin_lock(&desc->iuspin);
- clear_bit(WDM_READ, &desc->flags);
responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
- if (!responding && !test_bit(WDM_DISCONNECTING, &desc->flags)
+ if (!desc->resp_count++ && !responding
+ && !test_bit(WDM_DISCONNECTING, &desc->flags)
&& !test_bit(WDM_SUSPENDING, &desc->flags)) {
rv = usb_submit_urb(desc->response, GFP_ATOMIC);
dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
@@ -521,10 +522,36 @@ retry:
desc->length -= cntr;
/* in case we had outstanding data */
- if (!desc->length)
+ if (!desc->length) {
clear_bit(WDM_READ, &desc->flags);
- spin_unlock_irq(&desc->iuspin);
+ if (--desc->resp_count) {
+ set_bit(WDM_RESPONDING, &desc->flags);
+ spin_unlock_irq(&desc->iuspin);
+
+ rv = usb_submit_urb(desc->response, GFP_KERNEL);
+ if (rv) {
+ dev_err(&desc->intf->dev,
+ "%s: usb_submit_urb failed with result %d\n",
+ __func__, rv);
+ spin_lock_irq(&desc->iuspin);
+ clear_bit(WDM_RESPONDING, &desc->flags);
+ spin_unlock_irq(&desc->iuspin);
+
+ if (rv == -ENOMEM) {
+ rv = schedule_work(&desc->rxwork);
+ if (rv)
+ dev_err(&desc->intf->dev, "Cannot schedule work\n");
+ } else {
+ spin_lock_irq(&desc->iuspin);
+ desc->resp_count = 0;
+ spin_unlock_irq(&desc->iuspin);
+ }
+ }
+ } else
+ spin_unlock_irq(&desc->iuspin);
+ } else
+ spin_unlock_irq(&desc->iuspin);
rv = cntr;
@@ -635,6 +662,9 @@ static int wdm_release(struct inode *inode, struct file *file)
if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
kill_urbs(desc);
+ spin_lock_irq(&desc->iuspin);
+ desc->resp_count = 0;
+ spin_unlock_irq(&desc->iuspin);
desc->manage_power(desc->intf, 0);
} else {
/* must avoid dev_printk here as desc->intf is invalid */
--
1.7.9.5
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