[L0] Use immediate command lists for external semaphore wait/signal#21930
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The L0 spec requires zeCommandListAppendWaitExternalSemaphoreExt and zeCommandListAppendSignalExternalSemaphoreExt to be called on immediate command lists. On Gen12, queues default to regular (non-immediate) command lists, causing these calls to fail with ZE_RESULT_ERROR_INVALID_ARGUMENT. Fix by obtaining an immediate command list via getImmCmdList() when the queue is not already using immediate command lists, ensuring external semaphore operations work on all platforms including Gen12. Fixes: URLZA-723
cperkinsintel
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May 5, 2026
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@intel/llvm-gatekeepers please consider merging |
pbalcer
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May 6, 2026
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@intel/llvm-gatekeepers please consider merging |
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uditagarwal97
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May 19, 2026
Revert "[L0] Use immediate command lists for external semaphore wait/signal (#21930)" This reverts commit e928aae. By putting the semaphore on an immediate command list, but still using the original regular command list for the other graphic operations, we introduce some unsoundness that can lead to races and problems where the regular command list is the default. The better choice in the short term is to simply require that SYCL queues that are intended for semaphore usage use immediate command lists. I have a separate PR (in progress) that will make that change to the docs and tests and introduces a verification. #22046
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The L0 spec requires zeCommandListAppendWaitExternalSemaphoreExt and zeCommandListAppendSignalExternalSemaphoreExt to be called on immediate command lists. On Gen12, queues default to regular (non-immediate) command lists, causing these calls to fail with
ZE_RESULT_ERROR_INVALID_ARGUMENT.
Fix by obtaining an immediate command list via getImmCmdList() when the queue is not already using immediate command lists, ensuring external semaphore operations work on all platforms including Gen12.