On Mon, 21 Sep 2009, Remy Bohmer wrote: > So, as workaround/test I made this change: > > Index: linux-2.6.31/drivers/serial/atmel_serial.c > =================================================================== > --- linux-2.6.31.orig/drivers/serial/atmel_serial.c 2009-09-21 > 19:44:48.000000000 +0200 > +++ linux-2.6.31/drivers/serial/atmel_serial.c 2009-09-21 > 19:45:15.000000000 +0200 > @@ -808,7 +808,8 @@ static int atmel_startup(struct uart_por > /* > * Allocate the IRQ > */ > - retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED, > + retval = request_irq(port->irq, atmel_interrupt, > + IRQF_SHARED | IRQF_NODELAY, > tty ? tty->name : "atmel_serial", port); > if (retval) { > printk("atmel_serial: atmel_startup - Can't get irq\n"); The serial irq cannot run in hard irq context. There are two solutions to this problem: 1) Use the other timer which is available on AT91. 2) Make the serial driver explicitely threaded and check in the hardirq handler whether the irq originated from the serial driver. If yes, disable it in the serial device and return IRQ_WAKE_THREAD otherwise return IRQ_NONE. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html