On Mon, Mar 12, 2012 at 11:11 AM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: >> > + /* RXIS but RXFE? Just clear the interrupt */ >> > + if(unlikely(fifotaken == 0)) >> > + writew(UART011_RTIS | UART011_RXIS, >> > + uap->port.membase + UART011_ICR); > > BTW, I don't see why we need any of this stuff. > > The problem as described is that the interrupt handler is called with one > of the receive flags set (UART011_RTIS or UART011_RXIS) but with > UART01x_FR_RXFE clear. > > The problem report indicates that this is caused when we switch from FIFO > mode to non-FIFO mode, and the FIFO contained some unread characters. > > That can only happen once we've enabled interrupts in the IMSC register, > which doesn't happen until later in the startup function. > > So: > > spin_lock_irq(&uap->port.lock); > uap->im = UART011_RTIM; > if (!pl011_dma_rx_running(uap)) > uap->im |= UART011_RXIM; > writew(uap->im, uap->port.membase + UART011_IMSC); > spin_unlock_irq(&uap->port.lock); > > clearing the transmit/receive interrupts here _before_ we unmask them > should be sufficient. Right! OK I'll cook a v2 patch according to this suggestion and request Chanho to test it. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
