This patch supersedes
[PATCH v2 3/3][media] mceusb: Show USB halt/stall error recovery
This patch schedules a USB reset device call following a USB clear
halt error. The issues solved, and patch implementation,
are similar to those found in
drivers/hid/usbhid/hid-core.c.
As seen on very rare occasions approximately one time per month
(mceusb device 2304:0225 in this sample)
Jul 27 2018 15:09:39
[59388.696941] mceusb 1-1.1.2:1.0: Error: urb status = -32 (RX HALT)
[59388.698838] mceusb 1-1.1.2:1.0: rx clear halt error -32
the device can get into RX or TX HALT state where usb_clear_halt()
also fails and also returns -EPIPE (HALT/STALL). After which, all
further mceusb device control and data I/O always fail with HALT/STALL.
Subsequently, the entire mceusb device no longer functions.
Cause and problem replication conditions remain unknown.
Further troubleshooting reveals usb_reset_device()
restores mceusb device operation.
Patch test 1:
Hot unplugging the mceusb device triggers USB RX HALT and
USB clear halt errors. A mceusb_dev_disconnect() call follows unplug.
This patch's reset device call invokes an extra
mceusb_dev_probe()
mceusb_dev_disconnect()
cycle, before the mceusb driver detaches.
The additional probe/disconnect verifies the patch's device reset
code executed.
But note this patch is for USB clear halt error cases not caused by
unplugging the mceusb device.
Patch test 2:
Simulate a RX HALT and a clear halt error with instrumented code in
the driver.
Jul 12 2019 19:41:18
[522745.263104] mceusb 1-1.3:1.0: set rx halt retval, 0
[522745.263943] mceusb 1-1.3:1.0: Error: rx urb status = -32 (RX HALT)
[522745.263970] mceusb 1-1.3:1.0: kevent 1 scheduled
[522745.264016] mceusb 1-1.3:1.0: kevent handler called (flags 0x2)
[522745.272883] mceusb 1-1.3:1.0: rx clear halt status = 0
[522745.272917] mceusb 1-1.3:1.0: stuck RX HALT state requires USB Reset
Device to clear
[522745.273005] mceusb 1-1.3:1.0: mceusb_dev_disconnect called
[522745.702815] usb 1-1.3: reset full-speed USB device number 14 using dwc_otg
[522745.836812] mceusb 1-1.3:1.0: mceusb_dev_probe called
[522745.836823] mceusb 1-1.3:1.0: acceptable bulk inbound endpoint found
[522745.836832] mceusb 1-1.3:1.0: acceptable bulk outbound endpoint found
...
The result matches what is expected when the device gets into
a real rx clear halt error case by itself.
This is the same sequence of messages when manually invoking
the ./usbreset command line utility with an unpatched mceusb driver.
Signed-off-by: A Sun <as10...@comcast.net>
---
drivers/media/rc/mceusb.c | 67 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 55 insertions(+), 12 deletions(-)
diff --git a/drivers/media/rc/mceusb.c b/drivers/media/rc/mceusb.c
index efffb1795..2e86876f2 100644
--- a/drivers/media/rc/mceusb.c
+++ b/drivers/media/rc/mceusb.c
@@ -467,6 +467,7 @@ struct mceusb_dev {
/* usb */
struct usb_device *usbdev;
+ struct usb_interface *usbintf;
struct urb *urb_in;
unsigned int pipe_in;
struct usb_endpoint_descriptor *usb_ep_out;
@@ -523,6 +524,7 @@ struct mceusb_dev {
unsigned long kevent_flags;
# define EVENT_TX_HALT 0
# define EVENT_RX_HALT 1
+# define EVENT_RST_PEND 31
};
/* MCE Device Command Strings, generally a port and command pair */
@@ -764,8 +766,15 @@ static void mceusb_dev_printdata(struct mceusb_dev *ir, u8
*buf, int buf_len,
static void mceusb_defer_kevent(struct mceusb_dev *ir, int kevent)
{
set_bit(kevent, &ir->kevent_flags);
+
+ if (test_bit(EVENT_RST_PEND, &ir->kevent_flags)) {
+ dev_dbg(ir->dev, "kevent %d dropped pending USB Reset Device",
+ kevent);
+ return;
+ }
+
if (!schedule_work(&ir->kevent))
- dev_err(ir->dev, "kevent %d may have been dropped", kevent);
+ dev_dbg(ir->dev, "kevent %d already scheduled", kevent);
else
dev_dbg(ir->dev, "kevent %d scheduled", kevent);
}
@@ -1404,28 +1413,59 @@ static void mceusb_deferred_kevent(struct work_struct
*work)
container_of(work, struct mceusb_dev, kevent);
int status;
+ dev_err(ir->dev, "kevent handler called (flags 0x%lx)",
+ ir->kevent_flags);
+
+ if (test_bit(EVENT_RST_PEND, &ir->kevent_flags)) {
+ dev_err(ir->dev, "kevent handler canceled pending USB Reset
Device");
+ return;
+ }
+
if (test_bit(EVENT_RX_HALT, &ir->kevent_flags)) {
usb_unlink_urb(ir->urb_in);
status = usb_clear_halt(ir->usbdev, ir->pipe_in);
+ dev_err(ir->dev, "rx clear halt status = %d", status);
if (status < 0) {
- dev_err(ir->dev, "rx clear halt error %d",
- status);
+ /*
+ * Unable to clear RX halt/stall.
+ * Will need to call usb_reset_device().
+ */
+ dev_err(ir->dev,
+ "stuck RX HALT state requires USB Reset Device
to clear");
+ usb_queue_reset_device(ir->usbintf);
+ set_bit(EVENT_RST_PEND, &ir->kevent_flags);
+ clear_bit(EVENT_RX_HALT, &ir->kevent_flags);
+
+ /* Cancel all other error events and handlers */
+ clear_bit(EVENT_TX_HALT, &ir->kevent_flags);
+ return;
}
clear_bit(EVENT_RX_HALT, &ir->kevent_flags);
- if (status == 0) {
- status = usb_submit_urb(ir->urb_in, GFP_KERNEL);
- if (status < 0) {
- dev_err(ir->dev,
- "rx unhalt submit urb error %d",
- status);
- }
+ status = usb_submit_urb(ir->urb_in, GFP_KERNEL);
+ if (status < 0) {
+ dev_err(ir->dev, "rx unhalt submit urb error = %d",
+ status);
}
}
if (test_bit(EVENT_TX_HALT, &ir->kevent_flags)) {
status = usb_clear_halt(ir->usbdev, ir->pipe_out);
- if (status < 0)
- dev_err(ir->dev, "tx clear halt error %d", status);
+ dev_err(ir->dev, "tx clear halt status = %d", status);
+ if (status < 0) {
+ /*
+ * Unable to clear TX halt/stall.
+ * Will need to call usb_reset_device().
+ */
+ dev_err(ir->dev,
+ "stuck TX HALT state requires USB Reset Device
to clear");
+ usb_queue_reset_device(ir->usbintf);
+ set_bit(EVENT_RST_PEND, &ir->kevent_flags);
+ clear_bit(EVENT_TX_HALT, &ir->kevent_flags);
+
+ /* Cancel all other error events and handlers */
+ clear_bit(EVENT_RX_HALT, &ir->kevent_flags);
+ return;
+ }
clear_bit(EVENT_TX_HALT, &ir->kevent_flags);
}
}
@@ -1589,6 +1629,7 @@ static int mceusb_dev_probe(struct usb_interface *intf,
goto urb_in_alloc_fail;
}
+ ir->usbintf = intf;
ir->usbdev = usb_get_dev(dev);
ir->dev = &intf->dev;
ir->len_in = maxp;
@@ -1696,6 +1737,8 @@ static void mceusb_dev_disconnect(struct usb_interface
*intf)
struct usb_device *dev = interface_to_usbdev(intf);
struct mceusb_dev *ir = usb_get_intfdata(intf);
+ dev_dbg(&intf->dev, "%s called", __func__);
+
usb_set_intfdata(intf, NULL);
if (!ir)
--
2.11.0
