commit https://github.com/asunxx/linux/commit/17fe3b51f4ad5202a876ea4c92b5d99d4e166823 Author: A Sun <as1033x@xxxxxxxxxxx> Date: Sun, 26 Mar 2017 13:24:18 -0400 Bug: RX -EPIPE failure with infinite loop and flooding of Mar 20 22:24:56 raspberrypi kernel: [ 2851.966506] mceusb 1-1.2:1.0: Error: urb status = -32 log message at 8000 messages per second. Bug trigger appears to be normal, but heavy, IR receiver use. Driver and Linux host become unusable after error. Also seen at https://sourceforge.net/p/lirc/mailman/message/34886165/ Fix: Message reports RX usb halt (stall) condition requiring usb_clear_halt() call in non-interrupt context to recover. Add driver workqueue call to perform this recovery based on method in use for the usbnet device driver. Tested with: Linux raspberrypi 4.4.50-v7+ #970 SMP Mon Feb 20 19:18:29 GMT 2017 armv7l GNU/Linux mceusb 1-1.2:1.0: Registered Pinnacle Systems PCTV Remote USB with mce emulator interface version 1 mceusb 1-1.2:1.0: 2 tx ports (0x1 cabled) and 2 rx sensors (0x1 active) Signed-off-by: A Sun <as1033x@xxxxxxxxxxx> --- drivers/media/rc/mceusb.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 66 insertions(+), 1 deletion(-) diff --git a/drivers/media/rc/mceusb.c b/drivers/media/rc/mceusb.c index 238d8ea..7b6f9e5 100644 --- a/drivers/media/rc/mceusb.c +++ b/drivers/media/rc/mceusb.c @@ -36,12 +36,13 @@ #include <linux/device.h> #include <linux/module.h> #include <linux/slab.h> +#include <linux/workqueue.h> #include <linux/usb.h> #include <linux/usb/input.h> #include <linux/pm_wakeup.h> #include <media/rc-core.h> -#define DRIVER_VERSION "1.92" +#define DRIVER_VERSION "1.93" #define DRIVER_AUTHOR "Jarod Wilson <jarod@xxxxxxxxxx>" #define DRIVER_DESC "Windows Media Center Ed. eHome Infrared Transceiver " \ "device driver" @@ -417,6 +418,7 @@ struct mceusb_dev { /* usb */ struct usb_device *usbdev; struct urb *urb_in; + unsigned int pipe_in; struct usb_endpoint_descriptor *usb_ep_out; /* buffers and dma */ @@ -454,6 +456,12 @@ struct mceusb_dev { u8 num_rxports; /* number of receive sensors */ u8 txports_cabled; /* bitmask of transmitters with cable */ u8 rxports_active; /* bitmask of active receive sensors */ + + /* kevent support */ + struct work_struct kevent; + unsigned long kevent_flags; +# define EVENT_TX_HALT 0 +# define EVENT_RX_HALT 1 }; /* MCE Device Command Strings, generally a port and command pair */ @@ -1025,6 +1033,23 @@ static void mceusb_process_ir_data(struct mceusb_dev *ir, int buf_len) } } +/* + * Workqueue task dispatcher + * for work that can't be done in interrupt handlers + * (mceusb_dev_recv() and mce_async_callback()) nor tasklets. + * Invokes mceusb_deferred_kevent() for recovering from + * error events specified by the kevent bit field. + */ +static void mceusb_defer_kevent(struct mceusb_dev *ir, int kevent) +{ + set_bit(kevent, &ir->kevent_flags); + if (!schedule_work(&ir->kevent)) { + dev_err(ir->dev, "kevent %d may have been dropped", kevent); + } else { + dev_dbg(ir->dev, "kevent %d scheduled", kevent); + } +} + static void mceusb_dev_recv(struct urb *urb) { struct mceusb_dev *ir; @@ -1052,6 +1077,11 @@ static void mceusb_dev_recv(struct urb *urb) return; case -EPIPE: + dev_err(ir->dev, "Error: urb status = %d (RX HALT)", + urb->status); + mceusb_defer_kevent(ir, EVENT_RX_HALT); + return; + default: dev_err(ir->dev, "Error: urb status = %d", urb->status); break; @@ -1170,6 +1200,37 @@ static void mceusb_flash_led(struct mceusb_dev *ir) mce_async_out(ir, FLASH_LED, sizeof(FLASH_LED)); } +/* + * Workqueue function + * for resetting or recovering device after occurrence of error events + * specified in ir->kevent bit field. + * Function runs (via schedule_work()) in non-interrupt context, for + * calls here (such as usb_clear_halt()) requiring non-interrupt context. + */ +static void mceusb_deferred_kevent(struct work_struct *work) +{ + struct mceusb_dev *ir = + container_of(work, struct mceusb_dev, kevent); + int status; + + if (test_bit(EVENT_RX_HALT, &ir->kevent_flags)) { + usb_unlink_urb(ir->urb_in); + status = usb_clear_halt(ir->usbdev, ir->pipe_in); + if (status < 0) { + dev_err(ir->dev, "rx clear halt error %d", + status); + return; + } + clear_bit(EVENT_RX_HALT, &ir->kevent_flags); + status = usb_submit_urb(ir->urb_in, GFP_KERNEL); + if (status < 0) { + dev_err(ir->dev, "rx unhalt submit urb error %d", + status); + return; + } + } +} + static struct rc_dev *mceusb_init_rc_dev(struct mceusb_dev *ir) { struct usb_device *udev = ir->usbdev; @@ -1336,6 +1397,9 @@ static int mceusb_dev_probe(struct usb_interface *intf, if (!ir->rc) goto rc_dev_fail; + ir->pipe_in = pipe; + INIT_WORK(&ir->kevent, mceusb_deferred_kevent); + /* wire up inbound data handler */ usb_fill_int_urb(ir->urb_in, dev, pipe, ir->buf_in, maxp, mceusb_dev_recv, ir, ep_in->bInterval); @@ -1405,6 +1469,7 @@ static void mceusb_dev_disconnect(struct usb_interface *intf) return; ir->usbdev = NULL; + cancel_work_sync(&ir->kevent); rc_unregister_device(ir->rc); usb_kill_urb(ir->urb_in); usb_free_urb(ir->urb_in); -- 2.1.4
