diff options
authorOliver Barta <>2019-06-19 10:16:39 +0200
committerGreg Kroah-Hartman <>2019-07-14 08:11:19 +0200
commit135d9ba3b285b9e42d21e0928dba4b05d24087c8 (patch)
parent0891268f36a21693df090e40a9f5fd9bae2e4eb9 (diff)
Revert "serial: 8250: Don't service RX FIFO if interrupts are disabled"
commit 3f2640ed7be838c3f05c0d2b0f7c7508e7431e48 upstream. This reverts commit 2e9fe539108320820016f78ca7704a7342788380. Reading LSR unconditionally but processing the error flags only if UART_IIR_RDI bit was set before in IIR may lead to a loss of transmission error information on UARTs where the transmission error flags are cleared by a read of LSR. Information are lost in case an error is detected right before the read of LSR while processing e.g. an UART_IIR_THRI interrupt. Signed-off-by: Oliver Barta <> Reviewed-by: Andy Shevchenko <> Fixes: 2e9fe5391083 ("serial: 8250: Don't service RX FIFO if interrupts are disabled") Cc: stable <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3f779d25ec0c..e26d87b6ffc5 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1869,8 +1869,7 @@ 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) &&
- iir & UART_IIR_RDI) {
+ if (status & (UART_LSR_DR | UART_LSR_BI)) {
if (!up->dma || handle_rx_dma(up, iir))
status = serial8250_rx_chars(up, status);