Hi, Pawel Laszczak <pawell@xxxxxxxxxxx> writes: >>>>> IRQF_ONESHOT can be used only in threaded handled. >>>>> " >>>>> * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished. >>>>> * Used by threaded interrupts which need to keep the >>>>> * irq line disabled until the threaded handler has been run. >>>>> " >>>> >>>>so? >>> >>> I don't understand why If I don't have threaded handler why I need IRQF_ONESHOT. >>> Why interrupt cannot be reenabled after hardirq handler finished ? >>> I do not use threaded handler so this flag seem unnecessary. >> >>Unless this has changed over the years, it was a requirement from IRQ susbystem. >> >> /* >> * Drivers are often written to work w/o knowledge about the >> * underlying irq chip implementation, so a request for a >> * threaded irq without a primary hard irq context handler >> * requires the ONESHOT flag to be set. Some irq chips like >> * MSI based interrupts are per se one shot safe. Check the >> * chip flags, so we can avoid the unmask dance at the end of >> * the threaded handler for those. >> */ >> if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE) >> new->flags &= ~IRQF_ONESHOT; > > From description I understand that it should be set when driver uses only > threaded handler without hard irq handler. > eg. > > ret = devm_request_threaded_irq(dev, data->usb_id_irq, > NULL, int3496_thread_isr, > IRQF_SHARED | IRQF_ONESHOT | > IRQF_TRIGGER_RISING | > IRQF_TRIGGER_FALLING, > dev_name(dev), data); > > It make sense, we don't have hard irq handler so we can't clear source of interrupt. > If we clear it immediately in interrupt controller then the same interrupt could > be raised again, because it was not cleared e.g in controller register. You are correct. Big mistake on my side. Apologies. -- balbi
