On 01/12/2017 04:19 PM, Tony Lindgren wrote: > * Grygorii Strashko <grygorii.strashko@xxxxxx> [170112 13:54]: >> On 01/12/2017 03:30 PM, Tony Lindgren wrote: >> >> Sry, but even if it looks better it might still race with PM runtime :( >> >>> - if (likely(pm_runtime_active(cdd->ddev.dev))) >>> + if (likely(atomic_read(&cdd->active))) >>> push_desc_queue(c); >>> else >> >> >> - CPU is here (-EINPROGRESS and active == 0) and then preempted >> - PM runtime will finish cppi41_runtime_resume and clean-up pending descs >> - CPU return here and adds desc to the pending queue >> - oops >> >> Am I wrong? > > We had cppi41_dma_issue_pending() getting called from atomic contex and > cppi41_runtime_resume() getting preempted where cppi41_dma_issue_pending() > would add to the queue. Again, I can be mistaken but cppi41_configure_channel() seems not atomic. cppi41_configure_channel()->dma_async_issue_pending() + documentation says "This function can be called in an interrupt context" And definitely it will be preemptive on RT :( > > If what you're saying can happen in some cases, then we again see the > WARN_ON(!list_empty(&cdd->pending)) in cppi41_runtime_suspend(). At least > so far I have no longer been able to make happen today. -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
