f_printer drive fail to disable USB in_ep

[lixuhui112]

Hello

  I encountered an impossible problem when I used the f_printer driver. In some cases, the driver would reset the software for the USB, call the printer_soft_reset function, and the printer_reset_interface function, all failed because of the failure of the usb_ep_disable (dev->in_ep).Cause the Linux kernel to crash. I have no way to do that, I hope I can get your help.

       Thank you very much！！！

my version linux_4.1.15

log:

printer_soft_reset

Failed to disable USB in_ep
rx_complete
INFO: rcu_preempt detected stalls on CPUs/tasks:
0: (1 GPs behind) idle=405/140000000000000/0 softirq=670/671 fqs=2101
(detected by 2, t=2102 jiffies, g=159, c=158, q=513)
Task dump for CPU 0:
mx6q_voucher_sc R running 0 140 139 0x00000002
[<804603f0>] (__schedule) from [<806b1498>] (logbuf_lock+0x0/0x4)
INFO: rcu_preempt detected stalls on CPUs/tasks:
0: (1 GPs behind) idle=405/140000000000000/0 softirq=670/671 fqs=8404
(detected by 2, t=8407 jiffies, g=159, c=158, q=2045)

[CarlosCasillas]

Hi Li,

The NXP Linux BSP doesn’t include printer class support as Device, however, it could be added using the hardware layer USB driver already included. From a software side, you could take a look at the printer support provided by the gadget API; you could check the following links:

http://www.linux-usb.org/gadget/

https://github.com/torvalds/linux/blob/master/drivers/usb/gadget/legacy/printer.c

Hope this will be useful for you.
Best regards!
/Carlos

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