Alan Cox wrote: >>> Now if we are unlucky and the IRQ gets in between the last byte of >>> transfer and clearing the active ignore IRQ flag we will still run the >>> completion handler >> I don't really get this. What happens if the IRQ is shared and the >> other device raises interrupt while the data transfer is still in >> progress? What prevents it from running the completion routine? [--snip--] > c) the IRQ beats the clearing of the ignore irq flag in which case it > won't execute the handler but the data transfer path will This case is where I fail to understand how it's supposed to work. If IRQ beats the clearing of the ignore irq flag && execution of completion routine from wq, it ignores the IRQ, right? The IRQ line remains asserted, so when the IRQ handler finishes, it's entered again immediately till nobody-cared kicks in and completely disable the IRQ line. ie. clear_bit(COMPLETION_RUN, ->flags); xfer bytes >> IRQ hits here if (test_and_set_bit(COMPLETION_RUN, ->flags) == 0) run_completion_routine(); ->active-ignore-irq = 0; -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
