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Sebastian Andrzej Siewior authored
This is a revert of commits d6773926 ("drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe") 6c69a454 ("drm/i915/gt: Mark context->active_count as protected by timeline->mutex") 6dcb85a0 ("drm/i915: Hold irq-off for the entire fake lock period") The existing code leads to a different behaviour depending on whether lockdep is enabled or not. Any following lock that is acquired without disabling interrupts (but needs to) will not be noticed by lockdep. This it not just a lockdep annotation but is used but an actual mutex_t that is properly used as a lock but in case of __timeline_mark_lock() lockdep is only told that it is acquired but no lock has been acquired. It appears that its purpose is just satisfy the lockdep_assert_held() check in intel_context_mark_active(). The other problem with disabling interrupts is that on PREEMPT_RT interrupts are also disabled which leads to problems for instance later during memory allocation. Add a CONTEXT_IS_PARKING bit to intel_engine_cs and set_bit/clear_bit it instead of mutex_acquire/mutex_release. Use test_bit in the two identified spots which relied on the lockdep annotation. Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by:
Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by:
bce45c26
