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authorVignesh R <vigneshr@ti.com>2018-02-08 18:25:41 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-28 13:40:22 +0100
commit2e9fe539108320820016f78ca7704a7342788380 (patch)
tree43c99da821bd05eaeb7e4072e379dfb795927bc3 /drivers/tty/serial
parent890fb16b4cdbc625b9213487c547793a775ad991 (diff)
downloadop-kernel-dev-2e9fe539108320820016f78ca7704a7342788380.zip
op-kernel-dev-2e9fe539108320820016f78ca7704a7342788380.tar.gz
serial: 8250: Don't service RX FIFO if interrupts are disabled
Currently, data in RX FIFO is read based on UART_LSR register state even if RDI and RLSI interrupts are disabled in UART_IER register. This is because when IRQ handler is called due to TX FIFO empty event, RX FIFO is serviced based on UART_LSR register status instead of UART_IIR status. This defeats the purpose of disabling UART RX FIFO interrupts during throttling(see, omap_8250_throttle()) as IRQ handler continues to drain UART RX FIFO resulting in overflow of buffer at tty layer. Fix this by making sure that driver drains UART RX FIFO only when UART_IIR_RDI is set along with UART_LSR_BI or UART_LSR_DR bits. Signed-off-by: Vignesh R <vigneshr@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
-rw-r--r--drivers/tty/serial/8250/8250_port.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 1328c7e..ffbb955 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1854,7 +1854,8 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
status = serial_port_in(port, UART_LSR);
- if (status & (UART_LSR_DR | UART_LSR_BI)) {
+ if (status & (UART_LSR_DR | UART_LSR_BI) &&
+ iir & UART_IIR_RDI) {
if (!up->dma || handle_rx_dma(up, iir))
status = serial8250_rx_chars(up, status);
}
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