Quoting Chris Wilson (2017-11-14 16:27:19) > Ages ago Rob Clark noted, > > "Currently with fence-array, we have a potential deadlock situation. If > we fence_add_callback() on an array-fence, the array-fence's lock is > acquired first, and in it's ->enable_signaling() callback, it will install > cbs on it's array-member fences, so the array-member's lock is acquired > second. > > But in the signal path, the array-member's lock is acquired first, and > the array-fence's lock acquired second." > > Rob proposed either extensive changes to dma-fence to unnest the > fence-array signaling, or to defer the signaling onto a workqueue. This > is a more refined version of the later, that should keep the latency > of the fence signaling to a minimum by using an irq-work, which is > executed asap. > > Reported-by: Rob Clark <robdclark@xxxxxxxxx> > Suggested-by: Rob Clark <robdclark@xxxxxxxxx> Testcase: igt/sw_sync/sync_multi_timeline_wait > References: 1476635975-21981-1-git-send-email-robdclark@xxxxxxxxx > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Rob Clark <robdclark@xxxxxxxxx> > Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx> > Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx> > Cc: Christian König <christian.koenig@xxxxxxx> _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
