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Subject[PATCH 07/12] gigaset: improve error recovery (v2)
Date
When the Gigaset base stops responding, try resetting the USB
connection to recover.

Impact: error handling improvement
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
---
drivers/isdn/gigaset/bas-gigaset.c | 69 +++++++++++++++++++++++------------
1 files changed, 45 insertions(+), 24 deletions(-)
diff --git a/drivers/isdn/gigaset/bas-gigaset.c b/drivers/isdn/gigaset/bas-gigaset.c
index 9e7108a..5ed1d99 100644
--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -134,6 +134,7 @@ struct bas_cardstate {
#define BS_ATRDPEND 0x040 /* urb_cmd_in in use */
#define BS_ATWRPEND 0x080 /* urb_cmd_out in use */
#define BS_SUSPEND 0x100 /* USB port suspended */
+#define BS_RESETTING 0x200 /* waiting for HD_RESET_INTERRUPT_PIPE_ACK */


static struct gigaset_driver *driver = NULL;
@@ -319,6 +320,21 @@ static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
return -EINVAL;
}

+/* set/clear bits in base connection state, return previous state
+ */
+static inline int update_basstate(struct bas_cardstate *ucs,
+ int set, int clear)
+{
+ unsigned long flags;
+ int state;
+
+ spin_lock_irqsave(&ucs->lock, flags);
+ state = ucs->basstate;
+ ucs->basstate = (state & ~clear) | set;
+ spin_unlock_irqrestore(&ucs->lock, flags);
+ return state;
+}
+
/* error_hangup
* hang up any existing connection because of an unrecoverable error
* This function may be called from any context and takes care of scheduling
@@ -350,12 +366,9 @@ static inline void error_hangup(struct bc_state *bcs)
*/
static inline void error_reset(struct cardstate *cs)
{
- /* close AT command channel to recover (ignore errors) */
- req_submit(cs->bcs, HD_CLOSE_ATCHANNEL, 0, BAS_TIMEOUT);
-
- //FIXME try to recover without bothering the user
- dev_err(cs->dev,
- "unrecoverable error - please disconnect Gigaset base to reset\n");
+ /* reset interrupt pipe to recover (ignore errors) */
+ update_basstate(cs->hw.bas, BS_RESETTING, 0);
+ req_submit(cs->bcs, HD_RESET_INTERRUPT_PIPE, 0, BAS_TIMEOUT);
}

/* check_pending
@@ -398,8 +411,13 @@ static void check_pending(struct bas_cardstate *ucs)
case HD_DEVICE_INIT_ACK: /* no reply expected */
ucs->pending = 0;
break;
- /* HD_READ_ATMESSAGE, HD_WRITE_ATMESSAGE, HD_RESET_INTERRUPTPIPE
- * are handled separately and should never end up here
+ case HD_RESET_INTERRUPT_PIPE:
+ if (!(ucs->basstate & BS_RESETTING))
+ ucs->pending = 0;
+ break;
+ /*
+ * HD_READ_ATMESSAGE and HD_WRITE_ATMESSAGE are handled separately
+ * and should never end up here
*/
default:
dev_warn(&ucs->interface->dev,
@@ -449,21 +467,6 @@ static void cmd_in_timeout(unsigned long data)
error_reset(cs);
}

-/* set/clear bits in base connection state, return previous state
- */
-inline static int update_basstate(struct bas_cardstate *ucs,
- int set, int clear)
-{
- unsigned long flags;
- int state;
-
- spin_lock_irqsave(&ucs->lock, flags);
- state = ucs->basstate;
- ucs->basstate = (state & ~clear) | set;
- spin_unlock_irqrestore(&ucs->lock, flags);
- return state;
-}
-
/* read_ctrl_callback
* USB completion handler for control pipe input
* called by the USB subsystem in interrupt context
@@ -762,7 +765,8 @@ static void read_int_callback(struct urb *urb)
break;

case HD_RESET_INTERRUPT_PIPE_ACK:
- gig_dbg(DEBUG_USBREQ, "HD_RESET_INTERRUPT_PIPE_ACK");
+ update_basstate(ucs, 0, BS_RESETTING);
+ dev_notice(cs->dev, "interrupt pipe reset\n");
break;

case HD_SUSPEND_END:
@@ -1429,6 +1433,7 @@ static void req_timeout(unsigned long data)

case HD_CLOSE_ATCHANNEL:
dev_err(bcs->cs->dev, "timeout closing AT channel\n");
+ error_reset(bcs->cs);
break;

case HD_CLOSE_B2CHANNEL:
@@ -1438,6 +1443,13 @@ static void req_timeout(unsigned long data)
error_reset(bcs->cs);
break;

+ case HD_RESET_INTERRUPT_PIPE:
+ /* error recovery escalation */
+ dev_err(bcs->cs->dev,
+ "reset interrupt pipe timeout, attempting USB reset\n");
+ usb_queue_reset_device(bcs->cs->hw.bas->interface);
+ break;
+
default:
dev_warn(bcs->cs->dev, "request 0x%02x timed out, clearing\n",
pending);
@@ -1930,6 +1942,15 @@ static int gigaset_write_cmd(struct cardstate *cs,
goto notqueued;
}

+ /* translate "+++" escape sequence sent as a single separate command
+ * into "close AT channel" command for error recovery
+ * The next command will reopen the AT channel automatically.
+ */
+ if (len == 3 && !memcmp(buf, "+++", 3)) {
+ rc = req_submit(cs->bcs, HD_CLOSE_ATCHANNEL, 0, BAS_TIMEOUT);
+ goto notqueued;
+ }
+
if (len > IF_WRITEBUF)
len = IF_WRITEBUF;
if (!(cb = kmalloc(sizeof(struct cmdbuf_t) + len, GFP_ATOMIC))) {
--
1.6.2.1.214.ge986c


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