projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| ba74a726 GKH |
1 | From ca8bb4aefb932e3da105f28cbfba36d57a931081 Mon Sep 17 00:00:00 2001 |
| 2 | From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> | |
| 3 | Date: Sun, 15 Feb 2015 18:32:16 +0100 | |
| 4 | Subject: serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO" | |
| 5 | ||
| 6 | From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> | |
| 7 | ||
| 8 | commit ca8bb4aefb932e3da105f28cbfba36d57a931081 upstream. | |
| 9 | ||
| 10 | This reverts commit 0aa525d11859c1a4d5b78fdc704148e2ae03ae13. | |
| 11 | ||
| 12 | The conditional RX-FIFO read seems to cause spurious interrupts and we | |
| 13 | see just: | |
| 14 | |serial8250: too much work for irq29 | |
| 15 | ||
| 16 | The previous behaviour was "default" for decades and Marvell's 88f6282 SoC | |
| 17 | might not be the only that relies on it. Therefore the Omap fix is | |
| 18 | reverted for now. | |
| 19 | ||
| 20 | Fixes: 0aa525d11859 ("tty: serial: 8250_core: read only RX if there is | |
| 21 | something in the FIFO") | |
| 22 | Reported-By: Nicolas Schichan <nschichan@freebox.fr> | |
| 23 | Debuged-By: Peter Hurley <peter@hurleysoftware.com> | |
| 24 | Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> | |
| 25 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 26 | ||
| 27 | --- | |
| 28 | drivers/tty/serial/8250/8250_core.c | 11 +++++------ | |
| 29 | 1 file changed, 5 insertions(+), 6 deletions(-) | |
| 30 | ||
| 31 | --- a/drivers/tty/serial/8250/8250_core.c | |
| 32 | +++ b/drivers/tty/serial/8250/8250_core.c | |
| 33 | @@ -2107,8 +2107,8 @@ int serial8250_do_startup(struct uart_po | |
| 34 | /* | |
| 35 | * Clear the interrupt registers. | |
| 36 | */ | |
| 37 | - if (serial_port_in(port, UART_LSR) & UART_LSR_DR) | |
| 38 | - serial_port_in(port, UART_RX); | |
| 39 | + serial_port_in(port, UART_LSR); | |
| 40 | + serial_port_in(port, UART_RX); | |
| 41 | serial_port_in(port, UART_IIR); | |
| 42 | serial_port_in(port, UART_MSR); | |
| 43 | ||
| 44 | @@ -2269,8 +2269,8 @@ dont_test_tx_en: | |
| 45 | * saved flags to avoid getting false values from polling | |
| 46 | * routines or the previous session. | |
| 47 | */ | |
| 48 | - if (serial_port_in(port, UART_LSR) & UART_LSR_DR) | |
| 49 | - serial_port_in(port, UART_RX); | |
| 50 | + serial_port_in(port, UART_LSR); | |
| 51 | + serial_port_in(port, UART_RX); | |
| 52 | serial_port_in(port, UART_IIR); | |
| 53 | serial_port_in(port, UART_MSR); | |
| 54 | up->lsr_saved_flags = 0; | |
| 55 | @@ -2363,8 +2363,7 @@ void serial8250_do_shutdown(struct uart_ | |
| 56 | * Read data port to reset things, and then unlink from | |
| 57 | * the IRQ chain. | |
| 58 | */ | |
| 59 | - if (serial_port_in(port, UART_LSR) & UART_LSR_DR) | |
| 60 | - serial_port_in(port, UART_RX); | |
| 61 | + serial_port_in(port, UART_RX); | |
| 62 | serial8250_rpm_put(up); | |
| 63 | ||
| 64 | del_timer_sync(&up->timer); |