> > The IRQ delivery is async to the I/O so this makes a lot of sense for all > > cases. > > I don't think that's true unless the controller is doing something funky > as in SET XFERMODE. Can you enlighten me? It is true for all cases. There is no synchronization between interrupt delivery and I/O cycles and both of them are asynchronous. It is especially obvious on older APIC based boxes that use a 4 wire bus to send interrupt messages around. This leads to suprising sequences like device raises IRQ kernel blocks device IRQ at chip kernel reads to post the block kernel does other stuff IRQ message finally arrives IRQ taken - 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
