Some selftests assume that nothing will attempt to grab these bitlocks
while they are held by the selftests. With GuC, for example, that is
not true because the hanging workloads may cause the GuC code to attempt
to grab them for a global reset, and that may cause it to end up
sleeping on the bit never waking up. Regardless whether that will be
the final solution for GuC, use clear_and_wake_up_bit() pending a more
thorough investigation on how this should be handled moving forward.
To be clear this needs to be a temporary solution. If we can't find
an in-kernel locking primitive to use here, we should at the very least
add lockdep annotation to these bitlocks with a thorough explanation
as to why we need to use bits.
v3:
- Use GEM_BUG_ON(test_and_set_bit()) rather than set_bit() to verify
the assumption that nothing is holding the reset locks when we
attempt to grab them. (Chris Wilson)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105150146.834052-1-thomas.hellstrom@linux.intel.com
Two simple selftests which test that both GT and engine workarounds are
not lost after either a full GPU reset, or after the per-engine ones.
(Including checks that one engine reset is not affecting workarounds not
belonging to itself.)
v2:
* Rebase for series refactoring.
* Add spinner for actual engine reset!
* Add idle reset test as well. (Chris Wilson)
* Share existing global_reset_lock. (Chris Wilson)
v3:
* intel_engine_verify_workarounds can be static.
* API rename. (Chris Wilson)
* Move global reset lock out of the loop. (Chris Wilson)
v4:
* Add missing rpm puts. (Chris Wilson)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181203125014.3219-5-tvrtko.ursulin@linux.intel.com
