gpu: nvgpu: Allow semaphores to be force released

Allow SW to force a semaphore release. Typically SW waits for a
semaphore to reach the value right before the semaphore release
value before doing a release. For example, assuming a semaphore
is to be released by SW by writing a 10 into the semaphore, the
code waits for the semaphore to get to 9 before writing 10.

The problem with this happens when trying to shutdown the GPU
unexpectedly. When aborting a channel after the GPU has terminated
the GPU is potantially no longer processing anything. If a SW
semaphore release is waiting on the semaphore to reach N-1 before
writing N to the semaphore N-1 may never get written by the GPU.
This obviously causes a hang in the SW shutdown. The solution is
to let SW force a semaphore release in the channel_abort case.

Bug 1816516
Bug 1807277

Change-Id: Ib8b4afd86102eacf372362b1748fb6ca04e6fa66
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1250021
(cherry picked from commit 2e9fa40902d2c4d5a1febe0bf2db420ce14bc633)
Reviewed-on: http://git-master/r/1261915
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

0 files changed, 0 insertions, 0 deletions