Hello, I wrote:
[PATCH] When the usb-serial cable is unpluged, the usb host controller
driver returns all scheduled URBs to usb-serial driver(cdc-acm.c), and
the usb-serial driver(cdc-acm.c) doesn't detect this exception,
continues to schedule the URBs, it causes a dead loop.
This change fixes this problem.
Signed-off-by: Wending Weng <wweng@xxxxxxxxxxxxxx>
[...]
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 38bfdb0..3cc3e18 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -372,8 +372,15 @@ static void acm_read_bulk(struct urb *urb)
list_add_tail(&rcv->list, &acm->spare_read_urbs);
list_add(&buf->list, &acm->spare_read_bufs);
spin_unlock(&acm->read_lock);
- /* nevertheless the tasklet must be kicked unconditionally
- so the queue cannot dry up */
+
+ /* Normally, the tasklet must be kicked unconditionally
+ so the queue cannot dry up, however, if the cable is
disconnected,
+ or whatever fatal error, it must not reschedule any URB */
+
+ // Stop rescheduling any URB in case the connection
is shutdown
+ if ((urb->status == -ESHUTDOWN) || (urb->status ==
-EPROTO))
+ return;
+
Documentation/CodingStyle, chapter 8:
The preferred style for long (multi-line) comments is:
/*
* This is the preferred style for multi-line
* comments in the Linux kernel source code.
* Please use it consistently.
*
* Description: A column of asterisks on the left side,
* with beginning and ending almost-blank lines.
*/
Oh, and:
Linux style for comments is the C89 "/* ... */" style.
Don't use C99-style "// ..." comments.
WBR, Sergei
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