[RFC PATCH 0/3] Improve USB Keyboard support for rpi3/rpi4

[RFC PATCH 0/3] Improve USB Keyboard support for rpi3/rpi4

[Jason Wessel]

For testing this patch series, I did apply the USB patches for the
rpi4 board which had not been merged yet.  Once the rpi4 USB changes
are eventually merged the keyboard delay issues will show up and I
imagine this issue is already a problem for other boards. This series
does not depend on rpi4 patches as the changes are in the core USB
functions.

I am not entirely certain about the change to the common/usb.c which
is why this is an RFC.  I am not sure if there would be other side
effects to other USB drivers.  I did test with a number of usb modules
attached including storage, ethernet, serial, wifi, keyboard, and
mouse without any issues.

----------------------------------------------------------------
Jason Wessel (3):
      xhci: Add polling support for USB keyboards
      usb_kbd: Do not fail the keyboard if it does not have an interrupt pending
      common/usb.c: Work around keyboard reporting "USB device not accepting new address"

 common/usb.c                 | 10 ++++++----
 common/usb_kbd.c             |  4 +++-
 drivers/usb/host/xhci-ring.c | 24 +++++++++++++++---------
 drivers/usb/host/xhci.c      | 10 +++++-----
 include/usb/xhci.h           |  5 +++--
 5 files changed, 32 insertions(+), 21 deletions(-)

[RFC PATCH 1/3] xhci: Add polling support for USB keyboards

[Jason Wessel]

The xhci driver was causing intermittent 5 second delays from the USB
keyboard polling hook.  Executing something like a "sleep 1" for
example would sleep for 5 seconds, unless an event occurred on
the USB bus to shorten the delay.

Modeled after the code in the DWC2 driver, a nonblock state was added
to quickly return instead of blocking for up to 5 seconds waiting for
an event before timing out.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 drivers/usb/host/xhci-ring.c | 24 +++++++++++++++---------
 drivers/usb/host/xhci.c      | 10 +++++-----
 include/usb/xhci.h           |  5 +++--
 3 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 86aeaab412..1f7b3a8e0b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -434,7 +434,8 @@ static int event_ready(struct xhci_ctrl *ctrl)
  * @param expected	TRB type expected from Event TRB
  * @return pointer to event trb
  */
-union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
+union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected,
+				    bool nonblock)
 {
 	trb_type type;
 	unsigned long ts = get_timer(0);
@@ -442,8 +443,11 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
 	do {
 		union xhci_trb *event = ctrl->event_ring->dequeue;
 
-		if (!event_ready(ctrl))
+		if (!event_ready(ctrl)) {
+			if (nonblock)
+				return NULL;
 			continue;
+		}
 
 		type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
 		if (type == expected)
@@ -493,7 +497,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
 
 	xhci_queue_command(ctrl, NULL, udev->slot_id, ep_index, TRB_STOP_RING);
 
-	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
 	field = le32_to_cpu(event->trans_event.flags);
 	BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
 	BUG_ON(TRB_TO_EP_INDEX(field) != ep_index);
@@ -501,7 +505,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
 		!= COMP_STOP)));
 	xhci_acknowledge_event(ctrl);
 
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
 	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
 		!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
 		event->event_cmd.status)) != COMP_SUCCESS);
@@ -509,7 +513,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
 
 	xhci_queue_command(ctrl, (void *)((uintptr_t)ring->enqueue |
 		ring->cycle_state), udev->slot_id, ep_index, TRB_SET_DEQ);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
 	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
 		!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
 		event->event_cmd.status)) != COMP_SUCCESS);
@@ -555,7 +559,7 @@ static void record_transfer_result(struct usb_device *udev,
  * @return returns 0 if successful else -1 on failure
  */
 int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
-			int length, void *buffer)
+			int length, void *buffer, bool nonblock)
 {
 	int num_trbs = 0;
 	struct xhci_generic_trb *start_trb;
@@ -714,8 +718,10 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
 
 	giveback_first_trb(udev, ep_index, start_cycle, start_trb);
 
-	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, nonblock);
 	if (!event) {
+		if (nonblock)
+			return -EINVAL;
 		debug("XHCI bulk transfer timed out, aborting...\n");
 		abort_td(udev, ep_index);
 		udev->status = USB_ST_NAK_REC;  /* closest thing to a timeout */
@@ -911,7 +917,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
 
 	giveback_first_trb(udev, ep_index, start_cycle, start_trb);
 
-	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
 	if (!event)
 		goto abort;
 	field = le32_to_cpu(event->trans_event.flags);
@@ -929,7 +935,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
 	if (GET_COMP_CODE(le32_to_cpu(event->trans_event.transfer_len))
 			== COMP_SHORT_TX) {
 		/* Short data stage, clear up additional status stage event */
-		event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+		event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
 		if (!event)
 			goto abort;
 		BUG_ON(TRB_TO_SLOT_ID(field) != slot_id);
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index ebd2954571..6f1748dee2 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -464,7 +464,7 @@ static int xhci_configure_endpoints(struct usb_device *udev, bool ctx_change)
 	xhci_flush_cache((uintptr_t)in_ctx->bytes, in_ctx->size);
 	xhci_queue_command(ctrl, in_ctx->bytes, udev->slot_id, 0,
 			   ctx_change ? TRB_EVAL_CONTEXT : TRB_CONFIG_EP);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
 	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
 		!= udev->slot_id);
 
@@ -660,7 +660,7 @@ static int xhci_address_device(struct usb_device *udev, int root_portnr)
 	ctrl_ctx->drop_flags = 0;
 
 	xhci_queue_command(ctrl, (void *)ctrl_ctx, slot_id, 0, TRB_ADDR_DEV);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
 	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags)) != slot_id);
 
 	switch (GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))) {
@@ -735,7 +735,7 @@ static int _xhci_alloc_device(struct usb_device *udev)
 	}
 
 	xhci_queue_command(ctrl, NULL, 0, 0, TRB_ENABLE_SLOT);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
 	BUG_ON(GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))
 		!= COMP_SUCCESS);
 
@@ -1138,7 +1138,7 @@ static int _xhci_submit_int_msg(struct usb_device *udev, unsigned long pipe,
 	 * (at most) one TD. A TD (comprised of sg list entries) can
 	 * take several service intervals to transmit.
 	 */
-	return xhci_bulk_tx(udev, pipe, length, buffer);
+	return xhci_bulk_tx(udev, pipe, length, buffer, nonblock);
 }
 
 /**
@@ -1158,7 +1158,7 @@ static int _xhci_submit_bulk_msg(struct usb_device *udev, unsigned long pipe,
 		return -EINVAL;
 	}
 
-	return xhci_bulk_tx(udev, pipe, length, buffer);
+	return xhci_bulk_tx(udev, pipe, length, buffer, false);
 }
 
 /**
diff --git a/include/usb/xhci.h b/include/usb/xhci.h
index 20e4a21066..875ddb2cd5 100644
--- a/include/usb/xhci.h
+++ b/include/usb/xhci.h
@@ -1255,9 +1255,10 @@ void xhci_setup_addressable_virt_dev(struct xhci_ctrl *ctrl,
 void xhci_queue_command(struct xhci_ctrl *ctrl, u8 *ptr,
 			u32 slot_id, u32 ep_index, trb_type cmd);
 void xhci_acknowledge_event(struct xhci_ctrl *ctrl);
-union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected);
+union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected, 
+				    bool nonblock);
 int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
-		 int length, void *buffer);
+		 int length, void *buffer, bool nonblock);
 int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
 		 struct devrequest *req, int length, void *buffer);
 int xhci_check_maxpacket(struct usb_device *udev);
-- 
2.17.1

[RFC PATCH 2/3] usb_kbd: Do not fail the keyboard if it does not have an interrupt pending

[Jason Wessel]

After the initial configuration some USB keyboard+mouse devices never
return any kind of event on the interrupt line.  In particular, the
device identified by "Cypress Cypress USB Keyboard / PS2 Mouse as
/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0/0003:04B4:0101.0001/input/input0"
never returns a data packet until the first external input event.

I found this was also true with some newer model Dell keyboards.

When the device is plugged into a xhci controller there is also no
point in waiting 5 seconds for a device that is never going to present
data, so the call to the interrupt service was changed to a
nonblocking operation for the controllers that support this.

With the patch applied, the rpi3 and rpi4 work well with the more
complex keyboard devices.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 common/usb_kbd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/common/usb_kbd.c b/common/usb_kbd.c
index b316807844..3c0056e1b9 100644
--- a/common/usb_kbd.c
+++ b/common/usb_kbd.c
@@ -519,7 +519,9 @@ static int usb_kbd_probe_dev(struct usb_device *dev, unsigned int ifnum)
 			   1, 0, data->new, USB_KBD_BOOT_REPORT_SIZE) < 0) {
 #else
 	if (usb_int_msg(dev, data->intpipe, data->new, data->intpktsize,
-			data->intinterval, false) < 0) {
+			data->intinterval, true) < 0) {
+		/* Read first packet if the device provides it, else pick it up later */
+		return 1;
 #endif
 		printf("Failed to get keyboard state from device %04x:%04x\n",
 		       dev->descriptor.idVendor, dev->descriptor.idProduct);
-- 
2.17.1

[RFC PATCH 3/3] common/usb.c: Work around keyboard reporting "USB device not accepting new address"

[Jason Wessel]

When resetting the rpi3 board sometimes it will display:
     USB device not accepting new address (error=0)

After the message appears, the usb keyboard will not work.  It seems
that the configuration actually did succeed however.  Checking the
device status for a return code of zero and continuing allows the usb
keyboard and other usb devices to work function.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 common/usb.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/common/usb.c b/common/usb.c
index aad13fd9c5..2f7f205444 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -1054,11 +1054,13 @@ static int usb_prepare_device(struct usb_device *dev, int addr, bool do_read,
 	dev->devnum = addr;
 
 	err = usb_set_address(dev); /* set address */
-
-	if (err < 0) {
-		printf("\n      USB device not accepting new address " \
+	if (err < 0)
+		debug("\n       usb_set_address return < 0\n");
+	if (err < 0 && dev->status != 0) {
+		printf("\n      USB device not accepting new address "	\
 			"(error=%lX)\n", dev->status);
-		return err;
+		if (dev->status != 0)
+			return err;
 	}
 
 	mdelay(10);	/* Let the SET_ADDRESS settle */
-- 
2.17.1

[RFC PATCH 3/3] common/usb.c: Work around keyboard reporting "USB device not accepting new address"

[Matthias Brugger]

On 25/06/2020 17:10, Jason Wessel wrote:
> When resetting the rpi3 board sometimes it will display:
>      USB device not accepting new address (error=0)
> 
> After the message appears, the usb keyboard will not work.  It seems
> that the configuration actually did succeed however.  Checking the
> device status for a return code of zero and continuing allows the usb
> keyboard and other usb devices to work function.
> 
> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
> ---
>  common/usb.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/common/usb.c b/common/usb.c
> index aad13fd9c5..2f7f205444 100644
> --- a/common/usb.c
> +++ b/common/usb.c
> @@ -1054,11 +1054,13 @@ static int usb_prepare_device(struct usb_device *dev, int addr, bool do_read,
>  	dev->devnum = addr;
>  
>  	err = usb_set_address(dev); /* set address */
> -
> -	if (err < 0) {
> -		printf("\n      USB device not accepting new address " \
> +	if (err < 0)
> +		debug("\n       usb_set_address return < 0\n");
> +	if (err < 0 && dev->status != 0) {
> +		printf("\n      USB device not accepting new address "	\
>  			"(error=%lX)\n", dev->status);
> -		return err;
> +		if (dev->status != 0)

Always true as you already checked "dev->status != 0" in the first if.

Regards,
Matthias

> +			return err;
>  	}
>  
>  	mdelay(10);	/* Let the SET_ADDRESS settle */
> 

[RFC PATCH 1/3] xhci: Add polling support for USB keyboards

[Matthias Brugger]

On 25/06/2020 17:10, Jason Wessel wrote:
> The xhci driver was causing intermittent 5 second delays from the USB
> keyboard polling hook.  Executing something like a "sleep 1" for
> example would sleep for 5 seconds, unless an event occurred on
> the USB bus to shorten the delay.
> 
> Modeled after the code in the DWC2 driver, a nonblock state was added
> to quickly return instead of blocking for up to 5 seconds waiting for
> an event before timing out.
> 
> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
> ---
>  drivers/usb/host/xhci-ring.c | 24 +++++++++++++++---------
>  drivers/usb/host/xhci.c      | 10 +++++-----
>  include/usb/xhci.h           |  5 +++--
>  3 files changed, 23 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 86aeaab412..1f7b3a8e0b 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -434,7 +434,8 @@ static int event_ready(struct xhci_ctrl *ctrl)
>   * @param expected	TRB type expected from Event TRB
>   * @return pointer to event trb
>   */
> -union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
> +union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected,
> +				    bool nonblock)
>  {
>  	trb_type type;
>  	unsigned long ts = get_timer(0);
> @@ -442,8 +443,11 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
>  	do {
>  		union xhci_trb *event = ctrl->event_ring->dequeue;
>  
> -		if (!event_ready(ctrl))
> +		if (!event_ready(ctrl)) {
> +			if (nonblock)
> +				return NULL;
>  			continue;
> +		}
>  
>  		type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
>  		if (type == expected)
> @@ -493,7 +497,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
>  
>  	xhci_queue_command(ctrl, NULL, udev->slot_id, ep_index, TRB_STOP_RING);
>  
> -	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
> +	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
>  	field = le32_to_cpu(event->trans_event.flags);
>  	BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
>  	BUG_ON(TRB_TO_EP_INDEX(field) != ep_index);
> @@ -501,7 +505,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
>  		!= COMP_STOP)));
>  	xhci_acknowledge_event(ctrl);
>  
> -	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
> +	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
>  	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
>  		!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
>  		event->event_cmd.status)) != COMP_SUCCESS);
> @@ -509,7 +513,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
>  
>  	xhci_queue_command(ctrl, (void *)((uintptr_t)ring->enqueue |
>  		ring->cycle_state), udev->slot_id, ep_index, TRB_SET_DEQ);
> -	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
> +	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
>  	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
>  		!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
>  		event->event_cmd.status)) != COMP_SUCCESS);
> @@ -555,7 +559,7 @@ static void record_transfer_result(struct usb_device *udev,
>   * @return returns 0 if successful else -1 on failure
>   */
>  int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
> -			int length, void *buffer)
> +			int length, void *buffer, bool nonblock)
>  {
>  	int num_trbs = 0;
>  	struct xhci_generic_trb *start_trb;
> @@ -714,8 +718,10 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
>  
>  	giveback_first_trb(udev, ep_index, start_cycle, start_trb);
>  
> -	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
> +	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, nonblock);
>  	if (!event) {
> +		if (nonblock)
> +			return -EINVAL;
>  		debug("XHCI bulk transfer timed out, aborting...\n");
>  		abort_td(udev, ep_index);
>  		udev->status = USB_ST_NAK_REC;  /* closest thing to a timeout */
> @@ -911,7 +917,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
>  
>  	giveback_first_trb(udev, ep_index, start_cycle, start_trb);
>  
> -	event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
> +	event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
>  	if (!event)
>  		goto abort;
>  	field = le32_to_cpu(event->trans_event.flags);
> @@ -929,7 +935,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
>  	if (GET_COMP_CODE(le32_to_cpu(event->trans_event.transfer_len))
>  			== COMP_SHORT_TX) {
>  		/* Short data stage, clear up additional status stage event */
> -		event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
> +		event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
>  		if (!event)
>  			goto abort;
>  		BUG_ON(TRB_TO_SLOT_ID(field) != slot_id);
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index ebd2954571..6f1748dee2 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -464,7 +464,7 @@ static int xhci_configure_endpoints(struct usb_device *udev, bool ctx_change)
>  	xhci_flush_cache((uintptr_t)in_ctx->bytes, in_ctx->size);
>  	xhci_queue_command(ctrl, in_ctx->bytes, udev->slot_id, 0,
>  			   ctx_change ? TRB_EVAL_CONTEXT : TRB_CONFIG_EP);
> -	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
> +	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
>  	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
>  		!= udev->slot_id);
>  
> @@ -660,7 +660,7 @@ static int xhci_address_device(struct usb_device *udev, int root_portnr)
>  	ctrl_ctx->drop_flags = 0;
>  
>  	xhci_queue_command(ctrl, (void *)ctrl_ctx, slot_id, 0, TRB_ADDR_DEV);
> -	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
> +	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
>  	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags)) != slot_id);
>  
>  	switch (GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))) {
> @@ -735,7 +735,7 @@ static int _xhci_alloc_device(struct usb_device *udev)
>  	}
>  
>  	xhci_queue_command(ctrl, NULL, 0, 0, TRB_ENABLE_SLOT);
> -	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
> +	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
>  	BUG_ON(GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))
>  		!= COMP_SUCCESS);
>  
> @@ -1138,7 +1138,7 @@ static int _xhci_submit_int_msg(struct usb_device *udev, unsigned long pipe,

the nonblock parameter is not documented in the comment. Would you mind to fix
this in the next round?

Regards,
Matthias

>  	 * (at most) one TD. A TD (comprised of sg list entries) can
>  	 * take several service intervals to transmit.
>  	 */
> -	return xhci_bulk_tx(udev, pipe, length, buffer);
> +	return xhci_bulk_tx(udev, pipe, length, buffer, nonblock);
>  }
>  
>  /**
> @@ -1158,7 +1158,7 @@ static int _xhci_submit_bulk_msg(struct usb_device *udev, unsigned long pipe,
>  		return -EINVAL;
>  	}
>  
> -	return xhci_bulk_tx(udev, pipe, length, buffer);
> +	return xhci_bulk_tx(udev, pipe, length, buffer, false);
>  }
>  
>  /**
> diff --git a/include/usb/xhci.h b/include/usb/xhci.h
> index 20e4a21066..875ddb2cd5 100644
> --- a/include/usb/xhci.h
> +++ b/include/usb/xhci.h
> @@ -1255,9 +1255,10 @@ void xhci_setup_addressable_virt_dev(struct xhci_ctrl *ctrl,
>  void xhci_queue_command(struct xhci_ctrl *ctrl, u8 *ptr,
>  			u32 slot_id, u32 ep_index, trb_type cmd);
>  void xhci_acknowledge_event(struct xhci_ctrl *ctrl);
> -union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected);
> +union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected, 
> +				    bool nonblock);
>  int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
> -		 int length, void *buffer);
> +		 int length, void *buffer, bool nonblock);
>  int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
>  		 struct devrequest *req, int length, void *buffer);
>  int xhci_check_maxpacket(struct usb_device *udev);
>