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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2015-02-15 18:32:16 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-07 03:06:51 +0100
commitca8bb4aefb932e3da105f28cbfba36d57a931081 (patch)
treea97a7cf075bde126a791c852d85a34709f527148
parent045f32dda9477d3ddf31a4fa862c487d0f747e33 (diff)
serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO"
This reverts commit 0aa525d11859c1a4d5b78fdc704148e2ae03ae13. The conditional RX-FIFO read seems to cause spurious interrupts and we see just: |serial8250: too much work for irq29 The previous behaviour was "default" for decades and Marvell's 88f6282 SoC might not be the only that relies on it. Therefore the Omap fix is reverted for now. Fixes: 0aa525d11859 ("tty: serial: 8250_core: read only RX if there is something in the FIFO") Reported-By: Nicolas Schichan <nschichan@freebox.fr> Debuged-By: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/serial/8250/8250_core.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index e3b9570a1ef..deae122c9c4 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2138,8 +2138,8 @@ int serial8250_do_startup(struct uart_port *port)
/*
* Clear the interrupt registers.
*/
- if (serial_port_in(port, UART_LSR) & UART_LSR_DR)
- serial_port_in(port, UART_RX);
+ serial_port_in(port, UART_LSR);
+ serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
@@ -2300,8 +2300,8 @@ dont_test_tx_en:
* saved flags to avoid getting false values from polling
* routines or the previous session.
*/
- if (serial_port_in(port, UART_LSR) & UART_LSR_DR)
- serial_port_in(port, UART_RX);
+ serial_port_in(port, UART_LSR);
+ serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
up->lsr_saved_flags = 0;
@@ -2394,8 +2394,7 @@ void serial8250_do_shutdown(struct uart_port *port)
* Read data port to reset things, and then unlink from
* the IRQ chain.
*/
- if (serial_port_in(port, UART_LSR) & UART_LSR_DR)
- serial_port_in(port, UART_RX);
+ serial_port_in(port, UART_RX);
serial8250_rpm_put(up);
del_timer_sync(&up->timer);