transceiver: Fix POWEROFF crash on USRP2/N200/X300 devices
Upon issuing POWEROFF command to a running transceiver, UHD
interfacing thread state may become undefined if the device
is stopped with I/O threads still active. Bad behavior is
device dependent with only network based USRP devices
affected. USB based device thread behavior stops and shutdowns
as expected. Tested with N200, X300, and B210.
Tested solutions include the following:
1. Set pthread_setcanceltype() with PTHREAD_CANCEL_ASYNCHRONOUS
2. Add sleep delay to allow I/O threads to timeout before
stopping the device
3. Wait for I/O threads to join after cancellation before stopping
the device
This patch resolves the issue by with the third approach. Number 1
is not guaranteed to always work with UHD internals as driver code
may explicitly set thread parameters. Using sleep calls to fix
order-of-operation issues is almost never a good idea.
Change-Id: Ib72ab98a27a02084b040319046c92d1c4157ae4c
1 file changed