On 07/30/2015 07:15 PM, Peter Hurley wrote:

On 07/30/2015 06:54 PM, John Ogness wrote:

quoted

uart_write_wakeup() should be called without holding the port lock.
Otherwise a possible recursive spinlock issue can occur, such as
the following callchain:

8250_core.c:serial8250_tx_chars() - called with port locked
 serial_core.c:uart_write_wakeup()
  tty_io.c:tty_wakeup()
   st_core.c:st_tty_wakeup()
    st_core.c:st_tx_wakeup()
     st_core.c:st_int_write()
      serial_core.c:uart_write() - locks port

NAK.

This is a bug in the N_TI_WL line discipline, specifically in the
st_tx_wakeup() function, which cannot perform the write synchronously.

This is a common line discipline bug, and typically fixed by performing
the wakeup operations from a kworker instead.

Also, seriously consider if you want to use that TI line discipline at all.

If you're using it only for bluetooth w/ kernel bluetooth stack, you don't
need btwilink + st_drv anyway.

Regards,
Peter Hurley