Calling serial maintainers... Please consider the following commit for merging in v4.1. f28c1d0a78a8c6a217ac5362cb719efa169ae2a7 Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open" This backs out a misguided optimisation that is causing pl011 driver deadlocks for some people in certain scenarios (my bad). The revert is self-contained and independent of the other changes I posted. Thanks ---Dave Original commit message: This reverts commit f2ee6dfa0e8597eea8b98d240b0033994e20d215. Jakub Kiciński observed that this patch can cause the pl011 driver to hang if if the only process with a pl011 port open is killed by a signal, pl011_shutdown() can get called with an arbitrary amount of data still in the FIFO. Calling _shutdown() with the TX FIFO non-empty is questionable behaviour and my itself be a bug. Since the affected patch was speculative anyway, and brings limited benefit, the simplest course is to remove the assumption that TXIS will always be left asserted after the port is shut down. Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/amba-pl011.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 5a4e9d5..6f5a072 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1639,6 +1639,9 @@ static int pl011_startup(struct uart_port *port) writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS); + /* Assume that TX IRQ doesn't work until we see one: */ + uap->tx_irq_seen = 0; + spin_lock_irq(&uap->port.lock); /* restore RTS and DTR */ @@ -1702,7 +1705,7 @@ static void pl011_shutdown(struct uart_port *port) spin_lock_irq(&uap->port.lock); uap->im = 0; writew(uap->im, uap->port.membase + UART011_IMSC); - writew(0xffff & ~UART011_TXIS, uap->port.membase + UART011_ICR); + writew(0xffff, uap->port.membase + UART011_ICR); spin_unlock_irq(&uap->port.lock); pl011_dma_shutdown(uap); -- 1.7.10.4 -- 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
