Merge commit 'perf/core' into perf/hw-breakpoint

Conflicts:
	kernel/Makefile
	kernel/trace/Makefile
	kernel/trace/trace.h
	samples/Makefile

Merge reason: We need to be uptodate with the perf events development
branch because we plan to rewrite the breakpoints API on top of
perf events.

7 files changed, 257 insertions, 103 deletions

diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c
index 234cc5d53312..44a58e6f8f65 100644
--- a/drivers/isdn/gigaset/asyncdata.c
+++ b/drivers/isdn/gigaset/asyncdata.c
@@ -334,7 +334,14 @@ static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
 	return startbytes - numbytes;
 }
 
-/* process a block of data received from the device
+/**
+ * gigaset_m10x_input() - process a block of data received from the device
+ * @inbuf:	received data and device descriptor structure.
+ *
+ * Called by hardware module {ser,usb}_gigaset with a block of received
+ * bytes. Separates the bytes received over the serial data channel into
+ * user data and command replies (locked/unlocked) according to the
+ * current state of the interface.
  */
 void gigaset_m10x_input(struct inbuf_t *inbuf)
 {
@@ -543,16 +550,17 @@ static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
 	return iraw_skb;
 }
 
-/* gigaset_send_skb
- * called by common.c to queue an skb for sending
- * and start transmission if necessary
- * parameters:
- *	B Channel control structure
- *	skb
+/**
+ * gigaset_m10x_send_skb() - queue an skb for sending
+ * @bcs:	B channel descriptor structure.
+ * @skb:	data to send.
+ *
+ * Called by i4l.c to encode and queue an skb for sending, and start
+ * transmission if necessary.
+ *
  * Return value:
- *	number of bytes accepted for sending
- *	(skb->len if ok, 0 if out of buffer space)
- *	or error code (< 0, eg. -EINVAL)
+ *	number of bytes accepted for sending (skb->len) if ok,
+ *	error code < 0 (eg. -ENOMEM) on error
  */
 int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 {
diff --git a/drivers/isdn/gigaset/bas-gigaset.c b/drivers/isdn/gigaset/bas-gigaset.c
index 781c4041f7b0..5ed1d99eb9f3 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:
@@ -1331,28 +1335,24 @@ static void read_iso_tasklet(unsigned long data)
 		rcvbuf = urb->transfer_buffer;
 		totleft = urb->actual_length;
 		for (frame = 0; totleft > 0 && frame < BAS_NUMFRAMES; frame++) {
-			if (unlikely(urb->iso_frame_desc[frame].status)) {
+			numbytes = urb->iso_frame_desc[frame].actual_length;
+			if (unlikely(urb->iso_frame_desc[frame].status))
 				dev_warn(cs->dev,
-					 "isochronous read: frame %d: %s\n",
-					 frame,
+					 "isochronous read: frame %d[%d]: %s\n",
+					 frame, numbytes,
 					 get_usb_statmsg(
 					    urb->iso_frame_desc[frame].status));
-				break;
-			}
-			numbytes = urb->iso_frame_desc[frame].actual_length;
-			if (unlikely(numbytes > BAS_MAXFRAME)) {
+			if (unlikely(numbytes > BAS_MAXFRAME))
 				dev_warn(cs->dev,
 					 "isochronous read: frame %d: "
 					 "numbytes (%d) > BAS_MAXFRAME\n",
 					 frame, numbytes);
-				break;
-			}
 			if (unlikely(numbytes > totleft)) {
 				dev_warn(cs->dev,
 					 "isochronous read: frame %d: "
 					 "numbytes (%d) > totleft (%d)\n",
 					 frame, numbytes, totleft);
-				break;
+				numbytes = totleft;
 			}
 			offset = urb->iso_frame_desc[frame].offset;
 			if (unlikely(offset + numbytes > BAS_INBUFSIZE)) {
@@ -1361,7 +1361,7 @@ static void read_iso_tasklet(unsigned long data)
 					 "offset (%d) + numbytes (%d) "
 					 "> BAS_INBUFSIZE\n",
 					 frame, offset, numbytes);
-				break;
+				numbytes = BAS_INBUFSIZE - offset;
 			}
 			gigaset_isoc_receive(rcvbuf + offset, numbytes, bcs);
 			totleft -= numbytes;
@@ -1433,6 +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:
@@ -1442,6 +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);
@@ -1934,6 +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))) {
diff --git a/drivers/isdn/gigaset/common.c b/drivers/isdn/gigaset/common.c
index e4141bf8b2f3..33dcd8d72b7c 100644
--- a/drivers/isdn/gigaset/common.c
+++ b/drivers/isdn/gigaset/common.c
@@ -22,6 +22,12 @@
 #define DRIVER_AUTHOR "Hansjoerg Lipp <hjlipp@web.de>, Tilman Schmidt <tilman@imap.cc>, Stefan Eilers"
 #define DRIVER_DESC "Driver for Gigaset 307x"
 
+#ifdef CONFIG_GIGASET_DEBUG
+#define DRIVER_DESC_DEBUG " (debug build)"
+#else
+#define DRIVER_DESC_DEBUG ""
+#endif
+
 /* Module parameters */
 int gigaset_debuglevel = DEBUG_DEFAULT;
 EXPORT_SYMBOL_GPL(gigaset_debuglevel);
@@ -32,6 +38,17 @@ MODULE_PARM_DESC(debug, "debug level");
 #define VALID_MINOR	0x01
 #define VALID_ID	0x02
 
+/**
+ * gigaset_dbg_buffer() - dump data in ASCII and hex for debugging
+ * @level:	debugging level.
+ * @msg:	message prefix.
+ * @len:	number of bytes to dump.
+ * @buf:	data to dump.
+ *
+ * If the current debugging level includes one of the bits set in @level,
+ * @len bytes starting at @buf are logged to dmesg at KERN_DEBUG prio,
+ * prefixed by the text @msg.
+ */
 void gigaset_dbg_buffer(enum debuglevel level, const unsigned char *msg,
 			size_t len, const unsigned char *buf)
 {
@@ -274,6 +291,20 @@ static void clear_events(struct cardstate *cs)
 	spin_unlock_irqrestore(&cs->ev_lock, flags);
 }
 
+/**
+ * gigaset_add_event() - add event to device event queue
+ * @cs:		device descriptor structure.
+ * @at_state:	connection state structure.
+ * @type:	event type.
+ * @ptr:	pointer parameter for event.
+ * @parameter:	integer parameter for event.
+ * @arg:	pointer parameter for event.
+ *
+ * Allocate an event queue entry from the device's event queue, and set it up
+ * with the parameters given.
+ *
+ * Return value: added event
+ */
 struct event_t *gigaset_add_event(struct cardstate *cs,
 				  struct at_state_t *at_state, int type,
 				  void *ptr, int parameter, void *arg)
@@ -398,6 +429,15 @@ static void make_invalid(struct cardstate *cs, unsigned mask)
 	spin_unlock_irqrestore(&drv->lock, flags);
 }
 
+/**
+ * gigaset_freecs() - free all associated ressources of a device
+ * @cs:		device descriptor structure.
+ *
+ * Stops all tasklets and timers, unregisters the device from all
+ * subsystems it was registered to, deallocates the device structure
+ * @cs and all structures referenced from it.
+ * Operations on the device should be stopped before calling this.
+ */
 void gigaset_freecs(struct cardstate *cs)
 {
 	int i;
@@ -506,7 +546,12 @@ static void gigaset_inbuf_init(struct inbuf_t *inbuf, struct bc_state *bcs,
 	inbuf->inputstate = inputstate;
 }
 
-/* append received bytes to inbuf */
+/**
+ * gigaset_fill_inbuf() - append received data to input buffer
+ * @inbuf:	buffer structure.
+ * @src:	received data.
+ * @numbytes:	number of bytes received.
+ */
 int gigaset_fill_inbuf(struct inbuf_t *inbuf, const unsigned char *src,
 		       unsigned numbytes)
 {
@@ -606,20 +651,22 @@ static struct bc_state *gigaset_initbcs(struct bc_state *bcs,
 	return NULL;
 }
 
-/* gigaset_initcs
+/**
+ * gigaset_initcs() - initialize device structure
+ * @drv:	hardware driver the device belongs to
+ * @channels:	number of B channels supported by device
+ * @onechannel:	!=0 if B channel data and AT commands share one
+ *		    communication channel (M10x),
+ *		==0 if B channels have separate communication channels (base)
+ * @ignoreframes:	number of frames to ignore after setting up B channel
+ * @cidmode:	!=0: start in CallID mode
+ * @modulename:	name of driver module for LL registration
+ *
  * Allocate and initialize cardstate structure for Gigaset driver
  * Calls hardware dependent gigaset_initcshw() function
  * Calls B channel initialization function gigaset_initbcs() for each B channel
- * parameters:
- *	drv		hardware driver the device belongs to
- *	channels	number of B channels supported by device
- *	onechannel	!=0: B channel data and AT commands share one
- *			     communication channel
- *			==0: B channels have separate communication channels
- *	ignoreframes	number of frames to ignore after setting up B channel
- *	cidmode		!=0: start in CallID mode
- *	modulename	name of driver module (used for I4L registration)
- * return value:
+ *
+ * Return value:
  *	pointer to cardstate structure
  */
 struct cardstate *gigaset_initcs(struct gigaset_driver *drv, int channels,
@@ -837,6 +884,17 @@ static void cleanup_cs(struct cardstate *cs)
 }
 
 
+/**
+ * gigaset_start() - start device operations
+ * @cs:		device descriptor structure.
+ *
+ * Prepares the device for use by setting up communication parameters,
+ * scheduling an EV_START event to initiate device initialization, and
+ * waiting for completion of the initialization.
+ *
+ * Return value:
+ *	1 - success, 0 - error
+ */
 int gigaset_start(struct cardstate *cs)
 {
 	unsigned long flags;
@@ -879,9 +937,15 @@ error:
 }
 EXPORT_SYMBOL_GPL(gigaset_start);
 
-/* gigaset_shutdown
- * check if a device is associated to the cardstate structure and stop it
- * return value: 0 if ok, -1 if no device was associated
+/**
+ * gigaset_shutdown() - shut down device operations
+ * @cs:		device descriptor structure.
+ *
+ * Deactivates the device by scheduling an EV_SHUTDOWN event and
+ * waiting for completion of the shutdown.
+ *
+ * Return value:
+ *	0 - success, -1 - error (no device associated)
  */
 int gigaset_shutdown(struct cardstate *cs)
 {
@@ -912,6 +976,13 @@ exit:
 }
 EXPORT_SYMBOL_GPL(gigaset_shutdown);
 
+/**
+ * gigaset_stop() - stop device operations
+ * @cs:		device descriptor structure.
+ *
+ * Stops operations on the device by scheduling an EV_STOP event and
+ * waiting for completion of the shutdown.
+ */
 void gigaset_stop(struct cardstate *cs)
 {
 	mutex_lock(&cs->mutex);
@@ -1020,6 +1091,14 @@ struct cardstate *gigaset_get_cs_by_tty(struct tty_struct *tty)
 	return gigaset_get_cs_by_minor(tty->index + tty->driver->minor_start);
 }
 
+/**
+ * gigaset_freedriver() - free all associated ressources of a driver
+ * @drv:	driver descriptor structure.
+ *
+ * Unregisters the driver from the system and deallocates the driver
+ * structure @drv and all structures referenced from it.
+ * All devices should be shut down before calling this.
+ */
 void gigaset_freedriver(struct gigaset_driver *drv)
 {
 	unsigned long flags;
@@ -1035,14 +1114,16 @@ void gigaset_freedriver(struct gigaset_driver *drv)
 }
 EXPORT_SYMBOL_GPL(gigaset_freedriver);
 
-/* gigaset_initdriver
+/**
+ * gigaset_initdriver() - initialize driver structure
+ * @minor:	First minor number
+ * @minors:	Number of minors this driver can handle
+ * @procname:	Name of the driver
+ * @devname:	Name of the device files (prefix without minor number)
+ *
  * Allocate and initialize gigaset_driver structure. Initialize interface.
- * parameters:
- *	minor		First minor number
- *	minors		Number of minors this driver can handle
- *	procname	Name of the driver
- *	devname		Name of the device files (prefix without minor number)
- * return value:
+ *
+ * Return value:
  *	Pointer to the gigaset_driver structure on success, NULL on failure.
  */
 struct gigaset_driver *gigaset_initdriver(unsigned minor, unsigned minors,
@@ -1095,6 +1176,13 @@ error:
 }
 EXPORT_SYMBOL_GPL(gigaset_initdriver);
 
+/**
+ * gigaset_blockdriver() - block driver
+ * @drv:	driver descriptor structure.
+ *
+ * Prevents the driver from attaching new devices, in preparation for
+ * deregistration.
+ */
 void gigaset_blockdriver(struct gigaset_driver *drv)
 {
 	drv->blocked = 1;
@@ -1110,7 +1198,7 @@ static int __init gigaset_init_module(void)
 	if (gigaset_debuglevel == 1)
 		gigaset_debuglevel = DEBUG_DEFAULT;
 
-	pr_info(DRIVER_DESC "\n");
+	pr_info(DRIVER_DESC DRIVER_DESC_DEBUG "\n");
 	return 0;
 }
 
diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c
index 2d91049571a4..cc768caa38f5 100644
--- a/drivers/isdn/gigaset/ev-layer.c
+++ b/drivers/isdn/gigaset/ev-layer.c
@@ -207,7 +207,6 @@ struct reply_t gigaset_tab_nocid[] =
 	/* leave dle mode */
 	{RSP_INIT,      0,  0,SEQ_DLE0,           201, 5, {0},             "^SDLE=0\r"},
 	{RSP_OK,      201,201, -1,                202,-1},
-	//{RSP_ZDLE,    202,202,  0,                202, 0, {ACT_ERROR}},//DELETE
 	{RSP_ZDLE,    202,202,  0,                  0, 0, {ACT_DLE0}},
 	{RSP_NODEV,   200,249, -1,                  0, 0, {ACT_FAKEDLE0}},
 	{RSP_ERROR,   200,249, -1,                  0, 0, {ACT_FAILDLE0}},
@@ -265,6 +264,7 @@ struct reply_t gigaset_tab_nocid[] =
 	{EV_SHUTDOWN,  -1, -1, -1,                 -1,-1, {ACT_SHUTDOWN}}, //FIXME
 
 	/* misc. */
+	{RSP_ERROR,    -1, -1, -1,                 -1, -1, {ACT_ERROR} },
 	{RSP_EMPTY,    -1, -1, -1,                 -1,-1, {ACT_DEBUG}}, //FIXME
 	{RSP_ZCFGT,    -1, -1, -1,                 -1,-1, {ACT_DEBUG}}, //FIXME
 	{RSP_ZCFG,     -1, -1, -1,                 -1,-1, {ACT_DEBUG}}, //FIXME
@@ -328,10 +328,9 @@ struct reply_t gigaset_tab_cid[] =
 	{RSP_INIT,     -1, -1,SEQ_HUP,            401, 5, {0},             "+VLS=0\r"}, /* hang up */ //-1,-1?
 	{RSP_OK,      401,401, -1,                402, 5},
 	{RSP_ZVLS,    402,402,  0,                403, 5},
-	{RSP_ZSAU,    403,403,ZSAU_DISCONNECT_REQ, -1,-1, {ACT_DEBUG}}, /* if not remote hup */
-	//{RSP_ZSAU,    403,403,ZSAU_NULL,          401, 0, {ACT_ERROR}}, //DELETE//FIXME -> DLE0 // should we do this _before_ hanging up for base driver?
-	{RSP_ZSAU,    403,403,ZSAU_NULL,            0, 0, {ACT_DISCONNECT}}, //FIXME -> DLE0 // should we do this _before_ hanging up for base driver?
-	{RSP_NODEV,   401,403, -1,                  0, 0, {ACT_FAKEHUP}}, //FIXME -> DLE0 // should we do this _before_ hanging up for base driver?
+	{RSP_ZSAU,    403, 403, ZSAU_DISCONNECT_REQ, -1, -1, {ACT_DEBUG} },
+	{RSP_ZSAU,    403, 403, ZSAU_NULL,            0,  0, {ACT_DISCONNECT} },
+	{RSP_NODEV,   401, 403, -1,                   0,  0, {ACT_FAKEHUP} },
 	{RSP_ERROR,   401,401, -1,                  0, 0, {ACT_ABORTHUP}},
 	{EV_TIMEOUT,  401,403, -1,                  0, 0, {ACT_ABORTHUP}},
 
@@ -474,8 +473,13 @@ static int cid_of_response(char *s)
 	//FIXME is ;<digit>+ at end of non-CID response really impossible?
 }
 
-/* This function will be called via task queue from the callback handler.
- * We received a modem response and have to handle it..
+/**
+ * gigaset_handle_modem_response() - process received modem response
+ * @cs:		device descriptor structure.
+ *
+ * Called by asyncdata/isocdata if a block of data received from the
+ * device must be processed as a modem command response. The data is
+ * already in the cs structure.
  */
 void gigaset_handle_modem_response(struct cardstate *cs)
 {
@@ -707,6 +711,11 @@ static void disconnect(struct at_state_t **at_state_p)
 	if (bcs) {
 		/* B channel assigned: invoke hardware specific handler */
 		cs->ops->close_bchannel(bcs);
+		/* notify LL */
+		if (bcs->chstate & (CHS_D_UP | CHS_NOTIFY_LL)) {
+			bcs->chstate &= ~(CHS_D_UP | CHS_NOTIFY_LL);
+			gigaset_i4l_channel_cmd(bcs, ISDN_STAT_DHUP);
+		}
 	} else {
 		/* no B channel assigned: just deallocate */
 		spin_lock_irqsave(&cs->lock, flags);
@@ -1429,11 +1438,12 @@ static void do_action(int action, struct cardstate *cs,
 		cs->gotfwver = -1;
 		dev_err(cs->dev, "could not read firmware version.\n");
 		break;
-#ifdef CONFIG_GIGASET_DEBUG
 	case ACT_ERROR:
-		*p_genresp = 1;
-		*p_resp_code = RSP_ERROR;
+		gig_dbg(DEBUG_ANY, "%s: ERROR response in ConState %d",
+			__func__, at_state->ConState);
+		cs->cur_at_seq = SEQ_NONE;
 		break;
+#ifdef CONFIG_GIGASET_DEBUG
 	case ACT_TEST:
 		{
 			static int count = 3; //2; //1;
diff --git a/drivers/isdn/gigaset/i4l.c b/drivers/isdn/gigaset/i4l.c
index 9b22f9cf2f33..654489d836cd 100644
--- a/drivers/isdn/gigaset/i4l.c
+++ b/drivers/isdn/gigaset/i4l.c
@@ -51,6 +51,12 @@ static int writebuf_from_LL(int driverID, int channel, int ack,
 		return -ENODEV;
 	}
 	bcs = &cs->bcs[channel];
+
+	/* can only handle linear sk_buffs */
+	if (skb_linearize(skb) < 0) {
+		dev_err(cs->dev, "%s: skb_linearize failed\n", __func__);
+		return -ENOMEM;
+	}
 	len = skb->len;
 
 	gig_dbg(DEBUG_LLDATA,
@@ -79,6 +85,14 @@ static int writebuf_from_LL(int driverID, int channel, int ack,
 	return cs->ops->send_skb(bcs, skb);
 }
 
+/**
+ * gigaset_skb_sent() - acknowledge sending an skb
+ * @bcs:	B channel descriptor structure.
+ * @skb:	sent data.
+ *
+ * Called by hardware module {bas,ser,usb}_gigaset when the data in a
+ * skb has been successfully sent, for signalling completion to the LL.
+ */
 void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *skb)
 {
 	unsigned len;
@@ -455,6 +469,15 @@ int gigaset_isdn_setup_accept(struct at_state_t *at_state)
 	return 0;
 }
 
+/**
+ * gigaset_isdn_icall() - signal incoming call
+ * @at_state:	connection state structure.
+ *
+ * Called by main module to notify the LL that an incoming call has been
+ * received. @at_state contains the parameters of the call.
+ *
+ * Return value: call disposition (ICALL_*)
+ */
 int gigaset_isdn_icall(struct at_state_t *at_state)
 {
 	struct cardstate *cs = at_state->cs;
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 8ff7e35c7069..6a8e1384e7bd 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -408,33 +408,28 @@ static int if_write_room(struct tty_struct *tty)
 	return retval;
 }
 
-/* FIXME: This function does not have error returns */
-
 static int if_chars_in_buffer(struct tty_struct *tty)
 {
 	struct cardstate *cs;
-	int retval = -ENODEV;
+	int retval = 0;
 
 	cs = (struct cardstate *) tty->driver_data;
 	if (!cs) {
 		pr_err("%s: no cardstate\n", __func__);
-		return -ENODEV;
+		return 0;
 	}
 
 	gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
 
-	if (mutex_lock_interruptible(&cs->mutex))
-		return -ERESTARTSYS; // FIXME -EINTR?
+	mutex_lock(&cs->mutex);
 
-	if (!cs->connected) {
+	if (!cs->connected)
 		gig_dbg(DEBUG_IF, "not connected");
-		retval = -ENODEV;
-	} else if (!cs->open_count)
+	else if (!cs->open_count)
 		dev_warn(cs->dev, "%s: device not opened\n", __func__);
-	else if (cs->mstate != MS_LOCKED) {
+	else if (cs->mstate != MS_LOCKED)
 		dev_warn(cs->dev, "can't write to unlocked device\n");
-		retval = -EBUSY;
-	} else
+	else
 		retval = cs->ops->chars_in_buffer(cs);
 
 	mutex_unlock(&cs->mutex);
@@ -621,6 +616,15 @@ void gigaset_if_free(struct cardstate *cs)
 	tty_unregister_device(drv->tty, cs->minor_index);
 }
 
+/**
+ * gigaset_if_receive() - pass a received block of data to the tty device
+ * @cs:		device descriptor structure.
+ * @buffer:	received data.
+ * @len:	number of bytes received.
+ *
+ * Called by asyncdata/isocdata if a block of data received from the
+ * device must be sent to userspace through the ttyG* device.
+ */
 void gigaset_if_receive(struct cardstate *cs,
 			unsigned char *buffer, size_t len)
 {
diff --git a/drivers/isdn/gigaset/isocdata.c b/drivers/isdn/gigaset/isocdata.c
index bed38fcc432b..9f3ef7b4248c 100644
--- a/drivers/isdn/gigaset/isocdata.c
+++ b/drivers/isdn/gigaset/isocdata.c
@@ -429,7 +429,7 @@ static inline int hdlc_buildframe(struct isowbuf_t *iwb,
 		return -EAGAIN;
 	}
 
-	dump_bytes(DEBUG_STREAM, "snd data", in, count);
+	dump_bytes(DEBUG_STREAM_DUMP, "snd data", in, count);
 
 	/* bitstuff and checksum input data */
 	fcs = PPP_INITFCS;
@@ -448,7 +448,6 @@ static inline int hdlc_buildframe(struct isowbuf_t *iwb,
 	/* put closing flag and repeat byte for flag idle */
 	isowbuf_putflag(iwb);
 	end = isowbuf_donewrite(iwb);
-	dump_bytes(DEBUG_STREAM_DUMP, "isowbuf", iwb->data, end + 1);
 	return end;
 }
 
@@ -482,6 +481,8 @@ static inline int trans_buildframe(struct isowbuf_t *iwb,
 	}
 
 	gig_dbg(DEBUG_STREAM, "put %d bytes", count);
+	dump_bytes(DEBUG_STREAM_DUMP, "snd data", in, count);
+
 	write = iwb->write;
 	do {
 		c = bitrev8(*in++);
@@ -583,7 +584,7 @@ static inline void hdlc_done(struct bc_state *bcs)
 		procskb->tail -= 2;
 		gig_dbg(DEBUG_ISO, "%s: good frame (%d octets)",
 			__func__, procskb->len);
-		dump_bytes(DEBUG_STREAM,
+		dump_bytes(DEBUG_STREAM_DUMP,
 			   "rcv data", procskb->data, procskb->len);
 		bcs->hw.bas->goodbytes += procskb->len;
 		gigaset_rcv_skb(procskb, bcs->cs, bcs);
@@ -878,6 +879,8 @@ static inline void trans_receive(unsigned char *src, unsigned count,
 			dobytes--;
 		}
 		if (dobytes == 0) {
+			dump_bytes(DEBUG_STREAM_DUMP,
+				   "rcv data", skb->data, skb->len);
 			gigaset_rcv_skb(skb, bcs->cs, bcs);
 			bcs->skb = skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN);
 			if (!skb) {
@@ -973,16 +976,17 @@ void gigaset_isoc_input(struct inbuf_t *inbuf)
 
 /* == data output ========================================================== */
 
-/* gigaset_send_skb
- * called by common.c to queue an skb for sending
- * and start transmission if necessary
- * parameters:
- *	B Channel control structure
- *	skb
- * return value:
- *	number of bytes accepted for sending
- *	(skb->len if ok, 0 if out of buffer space)
- *	or error code (< 0, eg. -EINVAL)
+/**
+ * gigaset_isoc_send_skb() - queue an skb for sending
+ * @bcs:	B channel descriptor structure.
+ * @skb:	data to send.
+ *
+ * Called by i4l.c to queue an skb for sending, and start transmission if
+ * necessary.
+ *
+ * Return value:
+ *	number of bytes accepted for sending (skb->len) if ok,
+ *	error code < 0 (eg. -ENODEV) on error
  */
 int gigaset_isoc_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 {